UNIVERSITY  OF  CALIFORNIA  PUBLICATIONS 

COLLEGE  OF  AGRICULTURE 
AGRICULTURAL  EXPERIMENT  STATION 

BERKELEY,   CALIFORNIA 

VINE  PRUNING  IN  CALIFORNIA 

PART  I. 
By  FREDERIC  T.  BIOLETTI 


The  native  vine  of  California   (Vitis  Calif ornica). 

BULLETIN  No.  241 

(Berkeley,  CaL) 


Printed  at  the  State  Printing  Office,  Friend  Wm.  Richardson,  Superintendent 


Benjamin  Ide  Wheeler,  President  of  the  University. 

EXPERIMENT    STATION   STAFF. 
Heads  of  Divisions. 

Thomas  Forsyth  Hunt,  Director. 

Eugene  W.  Hilgard,  Agricultural  Chemistry   (Emeritus). 

Edward  J.  Wickson,  Horticulture. 

Herbert  J.  Webber,  Director  Citrus  Experiment  Station  ;   Plant  Breeding. 

Hubert   E.   Van   Norman,  Vice-Director   and   Dean   of   the   University   Farm    School 

Dairy  Management. 
William  A.  Setchell,  Botany. 
Myer  E.  Jaffa,  Nutrition. 

Robert  H.  Loughridge,  Soil  Chemistry  and  Physics  (Emeritus). 
Charles  W.  Woodworth,  Entomology. 
Ralph  E.  Smith,  Plant  Pathology. 
J.  Eliot  Coit,  Citriculture. 
John  W.  Gilmore,  Agronomy. 
Charles  F.  Shaw,  Soil  Technology. 

John  W.  Gregg,  Landscape  Gardening  and  Floriculture. 
Bernard  A.   Etcheverry,  Irrigation. 
Frederic  T.  Bioletti,  Viticulture  and  Enology. 
Warren  T.  Clarke,  Agricultural  Extension. 
John  S.  Burd,  Agricultural  Chemistry. 
Charles  B.  Lipman,  Soil  Chemistry  and  Bacteriology. 
Clarence  M.  Haring,  Veterinary  Science  and  Bacteriology. 
Ernest  B.  Babcock,  Genetics. 
Gordon  H.  True,  Animal  Husbandry. 
James  T.  Barrett,  Plant  Pathology. 
Fritz  W.  Woll,  Animal  Nutrition. 
Burr  B.  Pratt,  Pomology. 

William  G.   Hummel,  Agricultural  Education. 
Frank  L.  Peterson,  Farm  Mechanics. 
David  N.  Morgan,  Assistant  to  the  Director. 
Mrs.  D.  L.  Bunnell,  Librarian. 


DIVISION  OF  VITICULTURE  AND  ENOLOGY. 

Frederic  T.   Bioletti.  L.   Bonnet. 

W.  V.  Cruess.  A.   E.  Way. 

F.  C.  H.  Flossfeder.  W.  F.  Oglesby. 


VINE  PRUNING  IN  CALIFORNIA. 


INTRODUCTION. 

Literature. — A  large  number  of  books  have  been  published  on  the 
pruning  of  the  vine  but  none  of  them  are  very  well  adapted  to  the  needs 
of  the  Calif ornian  vine  grower.  Most  publications  in  English  refer  to 
methods  suited  to  the  Eastern  States  and  to  Eastern  varieties  or  to  the 
conditions  of  hot-house  cultivation.  Foreign  publications,  besides  being 
more  or  less  inaccessible,  are  adaptecf  to  conditions  different  from  those 
of  the  Pacific  Slope  or  treat  the  subject  so  widely  that  the  grower  is  at  a 
loss  to  choose  from  such  a  mass  of  material. 

In  1897  the  College  of  Agriculture  published  Bulletin  119,  "Vine 
Pruning,"  for  which  there  was  so  much  demand  that  the  edition  was 
quickly  exhausted.  This  bulletin  was  revised  and  republished  in  the 
Report  for  1897-98,  appearing  in  1900.  This  edition  has  also  been 
long  exhausted.  In  1907  Bulletin  193  was  issued  containing  articles 
on  the  ' '  Pruning  of  Young  Vines ' '  and  the  ' '  Pruning  of  the  Sultanina. ' ' 
Of  this,  also,  there  remain  no  copies  available  for  distribution. 

Need  of  the  Bulletin. — The  demand  for  information  on  vine  pruning 
still  continues  and  its  necessity  is  made  evident  by  the  unsightly,  de- 
fective and  unprofitable  condition  of  many  of  our  vineyards.  This 
seems  a  suitable  time  for  the  publication  of  a  new  bulletin  which  will 
incorporate  the  experience  of  the  older  and  more  skillful  grape  growers 
and  the  result  of  the  experiments  and  observations  of  the  Experiment 
Station  workers.  The  constant  influx  of  new  settlers  who  are  planting 
and  growing  vines  with  little  knowledge  of  the  methods  which  have 
proved  best  in  California  and  the  opening  up  of  new  Vine-growing 
districts  make  necessary  some  guide  that  will  help  to  avoid  the  numer- 
ous mistakes  made  in  the  past. 

Definition. — The  term  pruning,  both  by  derivation  and  usage,  is 
applied  to  various  operations  which  consist  in  cutting  off  certain  portions 
of  the  vine.  There  are  other  operations,  however,  the  purpose  of  which 
is  similar  or  identical,  which  must  logically  and  for  convenience  be  dis- 
cussed at  the  same  time.  Some  of  these  are  the  removal  of  buds  and 
shoots  by  other  means  than  cutting  and  the  attachment  of  the  vine  or 
its  parts  to  stakes,  wires,  or  other  supports.  For  this  reason  some 
writers  call  the  subject  the  "pruning  and  training  of  the  vine."  The 
word  "training,"  however,  is  misleading  when  applied  to  any  of  the 
vineyard  operations  used  in  California.  It  implies  methods  of  shaping 
the  vine  which  we  do  not  use  and  does  not  properly  describe  the  various 
operations  of  suckering,  disbudding,  water-sprouting  and  the  attach- 
ment of  fruit  canes  which  we  do  use.     The  word  pruning,  moreover, 


—  4  - 

seems  sufficient  alone,  as  all  the  other  operations  follow  and  are  necessi- 
tated by  the  methods  of  cutting  or  pruning-proper  adopted. 

Objects. — The  main  objects  of  pruning,  in  the  wider  sense,  are  first, 
to  give  the  vine  a  suitable  form  and  to  conserve  this  form ;  and  second, 
to  so  regulate  the  bearing  that  the  maximum  quality  and  quantity  of 
crop  may  be  obtained  for  a  long  series  of  years  at  the  minimum  expense. 

Scope. — The  crop  possibilities  of  a  vineyard,  both  as  regards  quantity 
and  quality,  depend  on  many  factors,  of  which  the  chief  are  the  char- 
acter of  soil  and  climate,  the  amount  of  available  water  and  the  nature 
of  the  variety  of  vine.  What  part  of  these  possibilities  is  realized 
depends  on  the  operations  of  the  vineyardist — on  how  he  handles  the 
soil  and  the  vine.  One  of  the  most  important  of  these  operations  is 
pruning.  By  improper  pruning  we  may  neutralize  the  most  favorable 
conditions  and  destroy  the  effect  of  the  most  careful  cultivation.  The 
skillful  pruner,  on  the  other  hand,  gives  his  vines  the  opportunity  to 
utilize  to  the  full  all  the  natural  and  cultural  advantages.  Many 
vineyards  produce  less  than  half  their  proper  average  crop  owing  to 
mistakes  in  pruning,  and  there  are  very  few  vineyards  in  the  State 
where  both  the  amount  and  quality  of  the  crop  could  not  be  increased 
considerably  by  improved  methods  of  pruning. 

There  are  two  great  difficulties  in  the  way  of  reforming  the  pruning 
methods  in  most  vineyards.  One  is  the  difficulty  of  obtaining  pruners 
possessed  of  the  necessary  skill  and  knowledge.  The  other  is  the  lack 
of  the  proper  knowledge  on  the  part  of  the  owner  of  the  vineyard.  Of 
these  difficulties  the  latter  is  by  far  the  most  serious  in  its  effects  and 
its  removal  would  in  most  cases  obviate  the  greatest  part  of  the  trouble 
due  to  the  former. 

Some  Results  of  Defective  Pruning. — In  order  to  emphasize  the  neces- 
sity for  proper  pruning  it  may  be  well  to  consider  some  of  the  results 
of  defective  pruning  as  shown  below : 

1.  Deficient  average  annual  amount  of  crop,  due  to — 

(a)  Delay  of  bearing  of  young  vines. 

(b)  Irregularity  of  development  of  vines. 

(c)  Failure  to  utilize  properly  full  vigor  of  best  vines. 

(d)  Lack  of  sufficient  fruit  buds. 

2.  Inferior  quality,  due  to — 

(a)  Over-bearing  of  weak  vines. 

(b)  Irregular  distribution  of  the  grapes  and  consequent  irreg- 

ular ripening. 

(c)  Injurious  contact  of  grapes  with  soil,  canes,  and  each  other. 

3.  High  cost  of  vineyard  operations  such  as — 
(a)   Cultivation,  plowing,  hoeing. 

(6)   Pruning,  suckering. 

(c)  Control  of  diseases,  oidium,  vine-hopper. 

(d)  Gathering,  trimming,  sorting,  culling. 


—  5  — 

4.  Shorter  life  of  vines,  due  to — 

(a)  Pruning  and  cultivation  wounds. 

(b)  Occasional  over-bearing. 

(c)  Growth  of  suckers. 

A  young  vine  under  average  conditions  in  California  should  bear  3 
paying  crop  at  three  years;  that  is,  in  the  autumn  of  the  third  leaf  or 
third  summer  in  the  field.  At  four  years  it  should  be  practically  in 
full  bearing.  Under  exceptionally  favorable  conditions,  bearing  may  be 
nearly  a  year  earlier  than  this.  In  the  cooler  regions  and  with  certain 
varieties,  a  year  longer  may  be  necessary.  These  results  can  be  obtained 
only  when  the  pruning  during  the  first  years  is  properly  done. 

Irregularity  of  development  of  individual  vines  is  incompatible  with 
the  highest  returns  for  the  whole  vineyard.  Vines  dwarfed  by  defec- 
tive pruning  can  not  compete  with  their  more  vigorous  neighbors  and 
will  fail  to  produce  a  full  crop.  Full  returns  from  a  vineyard  can  be 
obtained  only  when  there  is  comparative  uniformity  of  vigor  in  the 
individual  vines.  This  uniformity  can  be  obtained  only  by  carefully 
adapting  the  pruning  to  each  case.  If  vigorous  and  weak  young  vines 
are  pruned  alike,  the  former  may  bear  nothing  and  increase  their 
vigor,  while  the  latter  may  bear  worthless  grapes  and  increase  their 
weakness. 

When  the  vines  reach  the  age  of  full  bearing,  the  failure  to  adapt  the 
pruning  to  the  individual  case  is  equally  disastrous.  A  method  of  prun- 
ing adapted  to  a  weak  vine  would  prevent  a  vigorous  vine  from  bearing 
and  waste  its  possibilities,  while  a  method  adapted  to  a  vigorous  vine 
would  cause  a  weak  vine  to  attempt  to  bear  a  large  crop  of  worthless 
grapes  and  perhaps  die  in  the  attempt. 

Certain  methods  of  pruning  may  result  in  an  abnormally  large  crop 
one  year,  though  usually  at  the  cost  of  quality.  Such  a  crop  is  always 
followed  by  a  small  one.  Alternate  bearing  of  this  kind  diminishes 
the  average  crop  of  a  term  of  years.  The  neglected  possibilities  of  one 
year  can  be  utilized  by  the  vine  only  in  part  during  the  following  year. 

Unless  the  pruner  can  distinguish  the  fruit  buds  he  may  fail  to  leave 
a  sufficient  number.  The  loss  from  this  cause  is  the  greater  the  more 
vigorous  the  vines,  and  with  certain  varieties  than  with  others. 

Bad  pruning  is  a  frequent  cause  of  inferior  quality.  When  the  crop 
is  too  large  for  the  vigor  of  the  vine  or  even  of  a  part  of  the  vine,  the 
grapes  will  be  small,  will  fail  to  develop  sugar,  flavor  or  color  and  may 
dry  up  or  sunburn  before  they  are  ripe.  These  defects  are  due  not 
so  much  to  the  total  weight  of  crop,  which  may  not  be  excessive,  as  to 
the  excessive  number  of  individual  grapes  and  bunches. 

Bad  pruning  results  in  uneven  and  improper  distribution  of  the 
grapes  on  a  vine.     This  is  particularly  harmful  to  shipping  grapes, 


—  6  — 

resulting  in  uneven  ripening  and  coloring.  The  grapes  are  subjected 
to  different  conditions  of  light  and  heat  according  to  their  distance 
from  the  ground  and  to  the  degree  in  which  they  are  shaded  by  the 
leaves  or  other  grapes. 

On  a  vine  of  unsuitable  form,  the  bunches  may  lie  on  the  ground  and 
be  contaminated  by  the  soil  and  subject  to  mildew  and  mold,  or  they 
may  be  entangled  with  each  other  or  with  the  canes,  making  it  impos- 
sible to  harvest  them  without  injury  or  loss. 

Not  only  is  the  crop  diminished  and  the  quality  injured  by  bad 
pruning,  but  the  cost  of  production  is  increased. 

Vines  of  proper  and  uniform  shape  can  be  plowed,  cultivated  and 
hoed  with  a  minimum  of  labor.  Such  vines  can  be  pruned  and  suckered 
at  much  less  cost  than  irregular,  misshapen  vines.  The  control  of  the 
vine-hopper  is  impossible  and  that  of  oidium  and  other  diseases  more 
difficult  unless  the  vines  are  of  regular,  standard  shape. 

The  harvesting  of  the  grapes,  especially  of  shipping  grapes,  is  much 
simpler  and  more  satisfactory  if  the  vines  are  well  pruned.  The  cost 
of  trimming  and  the  loss  in  culls  are  much  diminished  and  the  shipping 
qualities  of  the  grapes  improved  by  proper  pruning. 

Finally,  the  useful  length  of  life  of  the  vineyard  depends  to  a  great 
extent  on  the  pruning.  Bad  pruning  not  only  results  in  large  pruning 
wounds  in  vital  parts  but  exposes  the  vine  to  serious  mechanical  inju- 
ries from  the  implements  of  cultivation.  These  wounds  and  injuries 
afford  means  of  ingress  to  injurious  parasites,  borers  of  various  kinds 
and  particularly  of  infection  by  black  knot  and  wood-rot  fungi. 
Irregularity  of  bearing,  also,  not  only  makes  the  vine  more  susceptible 
to  attacks  of  this  kind,  but  occasional  excessive  crops  may  actually  kill 
vines.  Certain  mistakes  in  pruning  favor  the  growth  of  suckers,  which 
appropriate  the  sap  and  cause  drying  up  and  final  death  of  the  crown 
and  trunk. 

Habit  and  Characteristics  of  the  Vine. 

Vitis  vinifera. — "With  a  few  unimportant  exceptions,  all  the  vines 
grown  for  their  fruit  in  California  are  varieties  of  Vitis  vinifera,  a  plant 
originating  apparently  in  the  region  south  of  the  Caucasus  but  now 
growing  wild  throughout  Western  Asia  and  the  Mediterranean  coun- 
tries and  cultivated  wherever  the  climate  is  suitable. 

It  is  sometimes  called  the  European  vine  because  grown  in  Europe 
more  largely  than  elsewhere,  though  many  of  our  most  valuable  varieties 
originated  in  Asia  and  Northern  Africa.  The  varieties  are  sometimes 
spoken  of  as  Californian  grapes  because  they  are  not  grown  east  of  the 
Rockies  or  to  any  great  extent  in  North  America  outside  of  California. 
They  include  all  the  varieties  of  vines  grown  in  California  except 
resistant  stocks  and  a  few  Labrusca  or  Eastern  varieties  such  as  Con- 


—  7  — 

cord  and  Pierce,  grown  to  a  limited  extent.  This  difference  of  species 
between  the  varieties  grown  in  the  Eastern  States  and  those  grown  in 
California  accounts  to  some  extent  for  the  differences  in  methods  of 
pruning,  though  the  difference  of  climate  is  an  equal  if  not  more 
important  factor. 

Vitis  vinifcra  and  its  varieties,  like  all  true  vines,  are  sarmentose 
plants,  that  is,  they  possess  long,  slender,  flexible  trunks  incapable  of 
self-support  and  attaching  themselves  by  means  of  tendrils  to  trees  or 
other  available  support.  If  allowed  to  grow  without  restriction,  they 
will  grow  to  the  top  of  high  trees  in  a  manner  similar  to  the  Labrusca 
vines  of  the  Eastern  States  or  the  wild  Vitis  Calif ornica  of  the  Pacific 
States.     (See  cover  cut  and  figure  1.) 

In  vineyards,  the  natural  habit  of  the  vine  is  modified  to  a  remarkable 
extent,  principally  by  pruning.  Most  cultivated  vinifera  vines  are 
given  the  form  of  a  low  self-supporting  shrub  with  a  short,  ri^id,  ver- 
tical trunk.  This  complete  change  of  natural  form  is  accomplished 
without  noticeable  injury  to  the  vigor  or  productive  capacity  of  the 
plant.  In  some  cases,  however,  it  may  be  carried  too  far  and  certain 
varieties  require  to  be  allowed  to  develop  in  a  somewhat  more  natural 
direction. 

Structure  of  a  Cultivated  Vine. — The  cultivated  vine  has  a  permanent 
framework,  consisting  of  root,  trunk  and  arms,  producing  an  annual 
growth  of  shoots,  leaves  and  fruit  above  ground  and  of  rootlets  below. 

The  root  and  its  branches  extend  in  all  directions  through  the  soil 
wherever  they  find  favorable  conditions.  Their  extent  is  limited  only 
by  the  competition  of  other  roots  or  by  mechanical  obstructions.  Their 
functions  are  to  collect  water  and  nutrient  salts  from  the  soil. 

The  trunk  is  usually  vertical  but  may  be  in  part  horizontal.  It 
varies  in  length  from  one  to  two  feet  in  low  vines  and  from-  three  to  six 
in  high.  Its  functions  are  the  conduction  and  storage  of  food  materials 
and  the  support  of  leaves  and  fruit. 

The  arms  are  the  smaller  divisions  of  the  framework  attached  to  the 
trunk.  They  vary  in  length  from  a  few  inches  to  a  maximum  of  about 
eighteen  inches.  They  may  rise  radially  from  the  top  of  the  trunk 
(vase  form)  or  along  its  whole  length  (vertical  cordon).  They  may  be 
in  one  vertical  plane  at  the  top  of  the  trunk  (fan-shape)  or  along  the 
whole  length  of  the  trunk  (horizontal  cordon).  Their  functions  are 
the  production  of  young  wood  and  the  proper  distribution  of  leaves  and 
fruit. 

The  young  wood  produced  each  year  by  the  arms  is  utilized  to  form 
the  spurs  and  canes  which  bear  the  leaves  and  fruit.  Its  total  length 
will  vary  in  different  cases  from  a  few  dozen  feet  to  several  hundred. 
In  all  cases  from  90  per  cent  to  98  per  cent  of  all  the  growth  is  removed 
at  each  pruning. 


—  8  — 

In  order  to  discuss  pruning  intelligently,  it  is  necessary  to  agree  on 
the  definition  of  the  technical  terms  used.  The  terms  and  definitions 
employed  here  are  in  nearly  all  cases  those  used  by  the  majority  of 


Californian  grape  growers.  An  attempt  has  been  made  to  have  them 
correspond  as  nearly  as  possible  to  the  terms  used  in  other  countries  and 
in  the  pruning  of  other  plants.  The  main  difficulty  in  this  respect  has 
been  with  the  terms  spur,  sucker;  water-sprout  and  lateral.     In  these 


—  9  — 

cases  the  usage  of  the  majority  of  Californian  grape  growers  has  been 

followed. 

terms  referring  to  the  form  and  structure 
of  a  cultivated  vine. 

Subterranean  Parts. 

Root  Tips.     The  extreme  ends  of  the  rootlets. 

Rootlets.     The  finest  roots,  the  growth  of  one  season. 

Root  Branches.  All  the  divisions  and  subdivisions  of  the  main  roots 
older  than  one  season. 

Main  Roots.  The  main  root  branches  arising  from  the  underground 
stem  or  tap  root. 

Tap  Root.  A  single  plunging  main  root  or  prolongation  of  the  under- 
ground stem. 

Root  Crown.  The  base  of  the  underground  stem  or  region  from  which 
originate  the  main  roots. 

Underground  Stem.  The  part  of  the  trunk  below  ground  from  the 
bottom  of  which  start  the  main  roots  or  tap  root. 

Aerial  Parts.     A.     Skeleton  or  Framework  After  Pruning. 
Trunk  or  Stem.     The  unbranched  body  of  the  vine. 
Head  or  Crown.     The  top  of  the  trunk,  or  region  from  which  arise  the 

arms  or  branches. 
Branches.     The  main  division  (when  long)  of  the  trunk. 
Arms.     The  main  divisions  (when  short)  of  the  trunk  or  branches. 
Spurs.     Short  pieces  of  the  bases  of  canes,  1  to  4  nodes  with  their  eyes. 
Fruit  Spurs.     Spurs  left  for  the  production  of  fruit. 
Wood  Spurs,     (a)  Renewal  Spurs.     Spurs  left  to  supply  fruit  spurs, 
or  fruit  canes  for  the  following  year,  1  to  2  eyes. 
(&)  Replacing  Spurs.     Spurs  left  to  supply  growth  for 
the  replacing  of  defective  arms,  1  eye. 
Fruit  Canes.     Canes  from  two-year-old  wood  left  for  fruit,  1^  to  6  feet 
long. 

Aerial  Parts.     B.     Annual  Growth. 

1.  Before  the  formation  of  leaves. 

Eyes.     The  compound  buds  on  the  canes. 

Fruit  Buds.  Buds  from  which  a  shoot,  bearing  flowers,  will  be  pro- 
duced. 

Wood  Buds.     Buds  from  which  sterile  shoots  will  be  produced. 

Base  Bud.     The  lowest  well  formed  eye  at  the  base  of  a  cane  or  spur. 

Latent  Buds.  Buds  which  have  remained  dormant  for  one  growing 
season  or  more. 

Adventitious  Buds.     Buds  arising  from  leafless  parts  of  the  wood. 

Main  Buds.     The  large  central  buds  of  the  eyes. 

Secondary  Buds.     The  small  lateral  buds  of  the  eyes. 


—  10  — 

2.  During  the  formation  of  leaves. 
Shoots.     The  succulent  growth  arising  from  a  bud. 
Fruit  Shoots.     Shoots  bearing  flowers. 
Wood  Shoots.     Sterile  shoots;  shoots  not  bearing  flowers. 
Water-sprouts.     Shoots  arising  from  dormant  or  adventitious  buds. 
Suckers.     Shoots  originating  below  the  surface  of  the  ground. 
Laterals.     Secondary  shoots  arising  from  buds  in  the  axils  of  the  leaves 
of  the  main  shoots. 

3.  After  the  fall  of  the  leaves,  before  pruning. 
Old  Wood.     Parts  of  the  vine  older  than  one  year. 
Ca)ies.     Young  wood  or  growth  of  the  current  season,  consisting  of  a 

series  of  nodes,  each  furnished  with  an  eye  and  separated  by  the 

smooth  portions  called  internodes. 
Fruit  Wood.     Canes  growing  out  of  two-year-old  wood. 
Sterile  Wood.     Canes  growing  out  of  wood  older  than  two  years. 

Roots. — The  pruner  has  little  to  do  with  the  roots  except  when  plant- 
ing or  in  cases  where  it  is  advisable  to  remove  certain  roots  of  young 
vines,  either  because  they  arise  from  the  scion  above  the  union  or  because 
they  are  too  near  the  surface.  Regular  root  pruning  at  intervals  of 
several  years  is  practised  in  some  regions,  but  there  seems  to  be  no 
sufficient  reason  for  the  practice  in  California.  Some  of  the  pruner 's 
operations  on  the  above  ground  portions  of  the  vine,  however,  may 
promote  or  restrict  root  growth. 

Every  year  the  vine  makes  a  new  growth  of  rootlets,  and  these  root- 
lets are  its  sole  means  of  obtaining  water  and  soil  nutrients.  These  it 
absorbs  by  means  of  the  young  cells  and'  root  hairs  within  an  inch  or 
two  of  the  root  tips.  The  rest  of  the  root  system  serves  to  conduct  the 
absorbed  material  to  the  aerial  parts  of  the  vine,  to  store  reserve  matters 
for  spring  growth  and  to  hold  the  vine  in  place.  The  position,  number 
and  vigor  of  the  roots  depend  more  on  the  nature  of  the  soil  and  cultural 
operations  than  on  anything  the  pruner  can  do. 

The  amount  of  root  growth  and  that  of  top  growth  are  mutually 
dependent.  Conditions  or  methods  which  stimulate  one  stimuate  the 
other  and  we  can  not  curtail  one  without  diminishing  the  other.  The 
position  of  the  root  system  is  due  partly  to  the  nature  of  the  variety  or 
species  of  vine  and  partly  to  the  conditions  of  penetrability,  moisture, 
aeration,  and  food  supply  of  the  soil.  The  roots  will  go  where  the  con- 
ditions are  most  favorable  and  nothing  we  can  do  which  does  not  change 
these  conditions  will  affect  the  position  of  the  roots  except  temporarily. 
The  rootlets  of  a  vine  grown  from  a  short  cutting  will  finally  occupy 
exactly  the  same  position  in  the  soil  as  those  of  a  vine  grown  from  a 
long  cutting. 


— 11  — 

We  can,  to  some  extent,  influence  the  position  of  the  main  roots  by 
appropriate  treatment  of  the  vine  when  young.  No  main  roots  should 
arise  nearer  than  four  or  five  inches  from  the  surface  or  they  will  be 
in  danger  of  injury  from  the  plow.  The  danger  of  shallow  rooting  is 
greatest  in  irrigated  soils  and  can  be  avoided  by  infrequent  and  deep 


Fig.   2.     Root  crown  of  a  four-year-old'  vine. 

irrigations,  by  avoiding  a  continually  wet  surface  in  the  growing  season 
during  the  first  two  years  and,  when  necessary,  by  removing  the  surface 
roots  while  they  are  small. 

The  best  root  system  is  that  in  which  all  the  main  roots  arise  from 
the  root  crown  at  the  bottom  of  the  underground  stem.     This  does  not 


—  12  — 

prevent  the  utilization  of  soil  at  higher  levels,  for  rootlets  will  grow 
into  all  regions  of  the  soil  where  the  conditions  are  favorable  whether 
below  or  above  the  main  roots.  No  injury  need  be  apprehended  from 
the  plowing  up  of  small  rootlets  as  they  will  re-form  as  fast  as  needed. 
The  destruction  of  a  main  root,  however,  is  harmful,  as  it  not  only 
destroys  all  the  rootlets  by  means  of  which  it  was  feeding  the  vine  but 
the  large  wound  may  allow  decay  organisms  to  attack  the  vine. 

The  supposed  superiority  of  a  tap  root  is  a  mere  superstition,  except 
in  so  far  as  it  involves  a  perfect  continuity  of  healthy  tissue  from  trunk 
to  root  branches.  Two,  three,  or  more  main  roots  from  the  root  crown 
are  equally  effective  providing  there  are  no  unhealed  wounds  on  the 
underground  stem  to  be  attacked  by  boring  insects  or  decay  fungi. 
(See  Fig.  2.)    . 

In  wet  soil  there  is  usually  a  definite  root  crown  at  6  to  8  inches  below 
the  surface.  The  planting  of  a  long  cutting  will  not  alter  this  condition 
as  the  roots  simply  start  where  the  moisture,  temperature  and  aeration 
are  most  favorable  and  all  below  this  point  dies.  In  drier  soil  a  short 
cutting  will  make  a  similar  root  crown,  but  on  a  longer  cutting  the  main 
roots  may  arise  at  various  levels.  There  is  no  objection  to  the  latter 
form  of  branching,  providing  some  roots  start  at  the  bottom  of  the  cut- 
ting and  completely  heal  the  surface.  A  root  crown  at  the  surface  of 
the  ground  is  very  objectionable  as  it  is  very  subject  to  injury  from 
plow  and  hoe,  and  consequently  subject  to  infection  by  black  knot  and 
wood  rot  fungi.  It  also  makes  clean  cultivation  and  the  perfect  and 
economical  removal  of  suckers  difficult.  A  clean,  smooth,  healthy 
underground  stem  of  at  least  six  inches  is  very  desirable. 

The  Trunk.  The  trunk  is  the  body,  we  might  say  the  life,  of  the 
vine.  Its  main  functions  are  to  support  the  bearing  wood  at  the  right 
height  from  the  ground,  to  carry  water  and  nutrient  salts  from  the 
roots  to  the  leaves  and  elaborated  food  from  the  leaves  to  the  roots. 
On  its  continued  healthy  state  depends  the  vigor,  crop  and  long  life  of 
the  whole  vine.  It  is  a  continuation  of  the  underground  stem  and 
should  be  perfectly  straight,  smooth  and  without  wound  or  branch  or 
cane  from  the  ground  to  the  head.  Its  length  or  height  depends  on  the 
variety,  climate,  and  form  of  pruning,  but  should  in  all  cases  be  suffi- 
cient to  allow  of  close  cultivation,  easy  hoeing,  and  proper  suckering. 
This  means  a  minimum  of  about  ten  inches.  Except  in  certain  forms 
of  trellis  and  cordon  pruning  it  should  never  exceed  thirty  inches.  A 
greater  height  is  expensive  to  develop  and  sustain,  and  gives  no  cor- 
responding advantage. 

The  trunk  is  formed  during  the  first  three  years  of  the  life  of  the  vine. 
Defects  acquired  during  this  period  can  never  be  wholly  remedied. 

The  Head  of  the  vine  is  the  top  of  the  trunk  or  region  from  which 


—  13  — 

the  arms  start.  At  first  it  is  more  or  less  indefinite,  the  spurs  from 
which  the  arms  finally  develop  being  at  various  heights  varying  six, 
eight  or  more  inches  but  none  nearer  than  six  inches  from  the  surface 
of  the  ground.  As  the  vine  develops,  the  arms  are  gradually  brought 
to  practically  the  same  level  by  the  removal  of  ill  placed  arms  before 
they  become  large  and  a  definite  head  formed  at  the  desired  height. 

Branches  or  long  major  divisions  of  the  trunk  are  not  used  in  any 
of  the  forms  of  pruning  adopted  in  California.  Their  only  use  is  in 
certain  forms  of  high  trellises  or  in  covering  an  arbor.  Where  the  trunk 
is  simply   elongated   without   branching   or   has   only   two   horizontal 


Pig.   3. — Carignane     vine     firteen     years     old. 
Well  formed  trunk,  head  and  arms ;  short  spurs. 

branches  at  the  same  level  the  form  is  called  a  cordon.     In  these  forms 
there  is  no  proper  head  or  crown. 

The  Arms  are  the  final  divisions  of  the  body  of  the  vine  which  bear 
the  spurs  and  fruit  canes.  They  should  be  long  enough  to  spread  the 
crop  sufficiently  to  give  all  the  bunches  the  necessary  sun,  space  and 
air  to  develop  properly.  They  should  not  be  long  enough  to  interfere 
with  cultivation  nor  to  be  in  danger  from  the  implements.  The  more 
vigorous  the  vine  and  the  higher  the  trunk  the  longer  the  arms  should 
be.     The  correct  length  will  vary  from  six  to  eighteen  inches. 


—  14  — 

The  arms  constantly  tend  to  become  too  long,  and  it  requires  skill, 
knowledge  and  foresight  on  the  part  of  the  pruner  to  keep  them  within 
the  required  limits.  Long  arms  tend  to  become  weak  and  unfruitful 
and  must  periodically  be  replaced  by  new  arms  developed  from  as  near 
the  head  of  the  vine  as  possible. 

The  number  of  the  arms  will  depend  on  the  style  of  pruning  adopted, 
and  on  the  size  of  the  vine.  With  very  short  pruning,  the  number  on  .i 
mature  vine  will  vary  from  three  or  four  on  a  small  growing  variety  in 
poor  soil  to  ten  or  fifteen  with  very  vigorous  vines.  With  longer  prun- 
ing the  number  of  arms  is  correspondingly  decreased,  while  with  long 
or  cane  pruning,  two  to  four  arms  are  all  that  should  be  given. 


Fig. 


4. — Muscat   vine,   over    fifteen   years  old.     Trunk  too   short,   arms  too  long,   but  head 

of  good  form. 


The  arrangement  of  the  arms  depends  principally  on  the  planting 
plan  and  method  of  cultivation.  When  the  vines  are  approximately 
equidistant  in  all  directions  and  cross  cultivation  is  practiced,  the  arms 
should  be  arranged  as  symetrically  as  possible  in  ' '  vase-form. ' '  When 
the  vines  are  planted  closer  together  in  rows  with  wider  "avenues" 
between  them,  especially  when  trellised,  cross  cultivation  is  impossible. 
In  these  cases  it  is  of  great  importance  that  the  arms  should  be  ' '  fan- 
shaped,"  that  is,  arranged  in  a  single  plane.  This  makes  it  possible  to 
plow  and  cultivate  very  close  to  the  vine  and  even  to  cut  out  some  of  the 
ridge  between  the  vines  with  horse  hoes  or  cultivators.     Care  in  shaping 


—  15  — 

the  young  vines  properly  in  this  respect  will  obviate  a  great  deal  of 
expensive  hand  hoeing  when  the  vines  are  large.  The  formation  of  the 
arms  takes  place  principally  during  the  third  and  fourth  years  and 
mistakes  made  at  this  time  can  be  remedied  only  imperfectly  later  and 
then  at  the  cost  of  mutilating  the  vine.  Trellised  vineyards  carelessly 
pruned  in  this  respect  often  have  a  strip  two  feet  wide  along  each  row 
to  be  worked  by  hand.  This  strip  can  be  reduced  to  six  inches  or 
less  by  carefully  forming  the  vines  when  young. 

At  and  near  the  ends  of  each  arm  are  left  pieces  of  young  wood  called 
Spurs  or  Fruit  Canes,  according  to  their  length.  The  spurs  vary  in 
length  according  to  their  purpose.  In  ordinary  short  pruning  most  of 
the  spurs  are  expected  to  produce  fruit.  Only  fruit  wood,  that  is, 
canes  growing  out  of  two-year-old  wood,  therefore,  can  be  used  for  this 
purpose.  The  average  length  of  a  fruit  spur  is  two  nodes  giving  three 
eyes  counting  the  base  bud  situated  at  the  base  of  the  cane  or  separated 
only  by  a  very  short  node  which  is  not  counted.  Fruit  spurs  will  vary 
in  length,  however,  from  one  node  to  four,  according,  principally,  to  the 
vigor  and  size  of  the  cane.  The  larger  the  cane  the  more  eyes  are  left 
on  the  spur  it  furnishes. 

A  Renewal  Spur  is  not  left  primarily  for  fruit.  Its  purpose  is  to 
furnish  shoots  from  which  the  fruit  spurs  and  fruit  canes  are  formed 
the  following  year.  In  ordinary  short  pruning,  the  fruit  spurs  function 
at  the  same  time  as  renewal  spurs.  In  long  pruning,  one  or  two 
renewal  spurs  must  be  left  below  each  fruit  cane  to  supply  fruit  canes 
for  the  following  year.  Such  spurs  usually  consist  of  two  full  inter- 
nodes,  but  in  some  cases  may  be  reduced  to  a  single  node  with  two  eyes 
including  the  base  bud.  As  renewal  spurs  are  not  intended  for  fruit, 
only  a  sufficient  number  must  be  left  to  insure  enough  properly  placed 
canes  for  the  next  pruning.  This  number  will  be  the  same  as  the 
number  of  fruit  canes  with  one,  two  or  three  extra  per  vine  to  provide 
against  the  failure  of  some  and,  when  necessary,  for  an  increased 
number  of  fruit  canes  the  following  year.  Sterile  or  fruit  wood  may  be 
used  for  this  purpose  as  either  will  produce  fruit  wood  for  the  following 
year. 

The  function  of  a  Replacing  Spur  is  to  provide  for  the  shortening 
or  replacing  of  an  over  elongated  or  otherwise  defective  arm.  It  con- 
sists of  only  one  internode  and  its  eye  or  even  of  simply  the  base  bud, 
if  this  is  well  formed.  As  it  is  intended  to  replace  an  arm,  it  is  chosen 
as  near  the  base  of  this  arm  as  is  practicable  without  necessitating  too 
large  a  wound  when  the  arm  is  removed.  Unless  the  arm  is  very  defec 
tive  its  removal  is  deferred  until  the  year  following  that  in  which  the 
replacing  spur  is  left.  In  this  way  no  crop  is  sacrificed.  The  first 
year  the  crop  is  borne  as  usual  on  spurs  or  canes  at  the  end  of  the  arm. 
The  next  year  the  replacing  spur  has  produced  fruit  wood  from  which 


—  16  — 

can  be  formed  a  fruit  spur  which  in  turn  develops  into  a  new  arm.  A 
replacing  spur  consists  always  of  sterile  wood,  as  it  is  made  from  a  cane 
growing  out  of  old  wood  near  the  base  of  the  arm.     Replacing  of  arms 


Fig.  5. — Cross-section  through  vine 
"eye"  showing  central  main  bud  and 
two  or  three  lateral  secondary  buds. 


should  be  done  with  sufficient  frequency  to  avoid  making  the  excessively 
large  wounds  which  would  be  necessary  if  the  arms  were  allowed  to 
become  very  old  and  large.     Spurs  left  to  produce  new  arms  on  develop- 


Fig.  6. — Cross-section  through  fruit 
bud  showing  two  embryonic  blossom 
bunches. 


ing  young  vines  are  left  longer  and  usually  consist  of  fruit  wood  as  they 
function  as  fruit  spurs  at  the  same  time. 

Some  varieties  of  vines  will  not  bear  satisfactory  crops  on  spurs  owing 
to  the  sterility  of  the  buds  near  the  base  of  the  cane  or  to  the  small 


—  17  — 

size  of  the  bunches,  which  makes  it  difficult  to  obtain  a  sufficient  number 
from  spurs  to  constitute  a  full  crop.  In  such  cases  it  is  necessary  to 
adopt  some  form  of  long  pruning,  with  fruit  canes.     A  fruit  cane  is  a 


Fig.  7. — Longitudinal  section  of  a 
fruit  bud  showing  an  embryonic  shoot 
with  embryonic  leaves  and  blossom 
bunch. 


piece  of  the  current  year's  fruit  wood  from  one  and  one  half  to  six  feet 
long.  ! 

Particular  attention  should  be  given  that  these  canes  consist  of  fruit 
wood,  that  is,  of  canes  growing  out  of  two-year-old  wood.     To  leave 


Fig.   8. — Longitudinal      section      of     a 
sterile  bud. 

sterile  wood,  suckers  or  water-sprouts  for  this  purpose  is  useless  and 
fails  to  utilize  the  vine's  possibilities  of  bearing.  Canes  less  than  two 
feet  long  are  not  advisable  as  they  are  difficult  to  attach  to  the  stake  or 
trellis  without  breaking.  No  advantage  on  the  other  hand  is  obtained 
2 — bul241 


—  18  — 

from  fruit  canes  longer  than  six  feet.  Fruit  canes  six  feet  long  will 
produce  as  many  fruiting  shoots  as  the  vine  can  develop  properly. 
Longer  canes,  indeed,  usually  fail  to  develop  any  more  fruit  as  a  larger 
proportion  of  the  buds  fail  to  start,  and  even  when  more  start,  the 
fruit  is  apt  to  be  inferior  in  size  and  quality.  Four  six-foot  fruit  canes 
with  five  or  six  renewal  spurs  is  about  the  maximum  for  the  strongest 
vines  with  our  methods  of  planting.  More  than  this  may  sometimes 
increase  the  crop,  but  nearly  always  at  the  expense  of  quality  and  often 
with  great  danger  of  injuring  the  vine  by  over-bearing.  This  latter 
danger  is  particularly  to  be  feared  with  vines  grafted  on  resistant  stock. 

The  buds  on  the  canes  are  usually  called  Eyes  by  the  pruner.  This 
is  a  convenient  term  as  they  are  more  than  simple  buds,  consisting  of  a 
main  central  bud  with  one  or  two  smaller  secondary  buds  within  the 
same  bud  scales.     (See  Fig.  5.) 

The  external  appearance  of  all  the  eyes  on  a  vine  is  similar.  They 
differ,  however,  in  the  important  respect  that  some  are  capable  of  pro- 
ducing a  fruit-bearing  shoot  and  others  are  not.  The  former  are  called 
Fruit  Buds,  the  latter  sterile  or  Wood  Buds.  If  a  thin  section  of  a 
bud  is  examined  under  a  low  power  microscope  it  is  possible  to  determine 
its  character.  The  embryo  blossom  bunches  can  be  seen  in  the  fruit 
buds. 

There  is  no  external  difference  in  appearance  between  fruitful  and 
sterile  buds,  and  the  pruner  has  no  means  of  determining  with  certainty 
whether  an  eye  contains  the  possibility  of  fruiting  or  not.  He  can, 
however,  tell  what  the  relative  probability  of  fruitfulness  is  with  dif- 
ferent eyes,  which,  for  this  purpose,  is  all  that  is  necessary.  This  he 
determines  by  the  position  of  the  eye  relative  to  the  cane  and  the  vine. 

The  greatest  probability  of  fruitfulness  occurs  in  the  eyes  of  canes 
which  have  been  produced  by  the  spurs  of  the  previous  year.  Or,  as 
the  pruner  expresses  it,  the  fruit  buds  are  on  the  canes  growing  out  of 
two-year-old  wood.  Canes  produced  by  older  wood,  that  is,  which 
have  grown  from  dormant  or  adventitious  buds,  are  usually  sterile. 
Water-sprout  canes  and  suckers,  therefore,  are  not  suitable  for  fruit 
spurs  or  fruit  canes. 

The  position  of  the  eye  on  the  cane  is  also  of  importance  in  judging 
of  its  probability  cf  fruitfulness.  The  base  bud  is  usually  sterile.  The 
first  and  second  eyes  are  usually  fruitful  with  most  vinifera  varieties. 
With  some  varieties,  the  probability  of  fruitfulness  is  not  great  until 
we  reach  the  fourth  or  fifth  eyes.  From  this  point  on  the  eyes  are 
usually  equally  fruitful  until  we  reach  a  point  where  the  cane  is  imper- 
fectly developed  or  badly  matured.  Sterility  of  the  lower  buds  makes 
long  pruning  necessary. 

A  bud  may  be  fruitful  in  varying  degrees.     A  thoroughly  fruitful 


—  19  — 

bud  of  most  vinifera  varieties  will  produce  on  the  average  two  bunches 
of  grapes  of  full  normal  size.  The  number  may  be  one,  two  or  three, 
according  to  variety.  A  less  fruitful  bud  will  produce  fewer  and 
smaller  bunches.  This  reduction  of  fruitfulness  may  continue  until  we 
find  buds  producing  bunches  which  are  little  more  than  tendrils  with  a 
few  grapes.  Such  buds  are  practically  sterile,  producing  few  blossoms 
or  grapes.  Their  bunches  are  easily  distinguished  from  the  loose 
bunches  due  to  the  dropping  of  the  blossoms  without  setting. 

Wood  Buds  are  those  which  contain  no  rudiments  of  blossoms  and 
are,  therefore,  incapable  of  yielding  fruit.  They  are  distinguished  by 
their  position,  which  can  be  inferred  from  what  has  been  said  regarding 
the  position  of  fruit  buds.  They  occur  principally  on  water-sprouts 
and  include  usually  also  base,  dormant  and  adventitious  buds. 

Some  of  the  buds  left  on  a  vine  do  not  develop  the  first  year,  or  pro- 
duce only  a  few  small  leaves.  Such  cases  are  particularly  frequent  in 
long  pruning.  These  buds  will  often  develop  the  second  year,  especially 
if  shorter  pruning  is  adopted.  These  buds  are  called  dormant  or  latent 
buds  and  are  usually  sterile. 

With  the  warm  weather  of  spring,  the  bud  commences  to  swell,  then 
to  elongate  and  finally  produces  a  growing  shoot  which  pushes  through 
the  bud  scales.  This  shoot  is  produced  by  the  main  bud.  If  the  vine 
is  vigorous  and  the  number  of  buds  limited,  one  or  both  of  the  secondary 
buds  may  start  and  produce  smaller  shoots.  Any  injury  to  the  main 
bud  results  in  the  starting  of  the  secondary  buds.  Cut  worms,  or  other 
gnawing  insects,  often  kill  the  main  bud  without  injuring  the  others. 
The  same  effect  may  be  produced  by  a  moderate  frost  after  the  shoots 
have  started.  A  heavy  spring  frost  will  sometimes  kill  all  the  buds  in 
a  started  eye. 

The  main  buds  on  fruit  wood  usually  produce  fruit  bearing  shoots. 
The  rudimentary  blossom  bunches  can  be  seen  after  the  shoot  has  grown 
a  few  inches.  There  are  usually  two,  or  more  rarely  one  or  three.  They 
may  occur  at  the  second  and  third,  the  third  and  fourth  or  the  fourth 
and  fifth  nodes.  (See  Fig.  9.)  Shoots  from  the  secondary  buds  may 
also  produce  fruit  but  the  bunches  are  smaller  and  less  numerous. 
Similar  small  bunches  may  be  produced  by  shoots  from  the  buds  of 
suckers  or  water-sprouts.  Other  shoots  are  sterile,  producing  only 
tendrils  in  the  place  of  fruit  and  are  called  wood  shoots. 

A  shoot  coming  from  a  dormant  or  adventitious  bud  on  the  old  wood 
is  called  a  water-sprout,  and  is  usually  sterile.  A  sucker  is  a  shoot 
coming  from  below  the  ground.  On  vines  which  are  properly  handled 
the  suckers  are  removed  carefully  and  completely  every  year  so  that 
few  are  produced,  and,  as  these  must  come  from  adventitious  buds, 
they  are  sterile.     If  the  removal  of  suckers  is  neglected  or  imperfect,  a 


—  20  — 

shoot  from  below  ground  may  arise  from  the  base  of  a  sucker  of  the 
previous  year  in  which  case  it  may  be  fruitful. 

As  a  shoot  grows,  it  produces  one  leaf  at  each  node  on  alternate  sides. 
Opposite  the  second,  third,  fourth  or  fifth  leaf  is  produced  a  blossom 
bunch  on  fruit  shoots  and  a  tendril  on  sterile  shoots.  The  next  one  or 
two  nodes  may  also  produce  bunches  or  tendrils.     As  the  shoot  elongates 


Fig.   9. — Blossom-bearing  shoot  of  Tokay  vine. 

further  it  produces  more  tendrils  but  not  at  all  nodes  in  vinifera 
varieties. 

In  the  axil  of  the  leaf,  that  is,  in  the  angle  between  the  leaf  stalk 
and  the  shoot,  occurs  a  bud.  Beside  this  bud  very  often  arises  a  side 
shoot  called  a  lateral.  These  laterals  may  be  very  short  or  may  grow 
out  and  form  large  lateral  canes.  Any  injury  to  the  growing  tip  of 
the  main  shoot  stimulates  the  production  and  growth  of  laterals.  Lat- 
erals of  some  varieties  may  produce  fruit  like  main  canes.     This  fruit 


—  21  — 

is  the  so-called  second  crop  and  is  usually  about  two  weeks  later  than 
the  main  crop.  Rarely  these  laterals  may  produce  secondary  laterals 
in  their  turn  which  in  a  few  varieties  may  produce  a  third  crop.  (See 
Fig.  10.) 

We  have  on  a  vine,  therefore,  fruit  wood  and  sterile  wood,  but  this 
distinction  is  not  absolute.  Some  of  the  buds  on  the  fruit  wood  may  be 
sterile  while  some  on  the  sterile  wood  may  be  fruitful.  The  proba- 
bilities of  fruitfulness,  however,  are  so  much  greater  in  one  case  than 
in  the  other  that  the  pruner  may  safely  proceed  as  though  it  were 
absolute.     The  difference  between  the  two  kinds  of  wood  varies  greatly 


Fig. 


10. — Fruit-bearing    cane    of    Black    Morocco,    showing    (I)    first    crop,    (II) 
second   crop,    and    (III)    third    crop. 


with  different  varieties.  On  a  Muscat  or  Alexandria  most  of  the  buds, 
even  on  water-sprout  canes,  contain  rudiments  of  blossoms,  while  on  a 
Sultanina  they  are  almost  always  sterile.  The  fruitfulness  of  all  kinds 
of  wood  moreover  depends  on  weather,  soil  and  cultural  conditions.  In 
some  cases  the  conditions  are  so  favorable  to  fruitfulness  that  even  the 
water-sprouts  bear.  Hot  summers,  certain  mechanical  injuries  to  the 
vine  and  grafting  on  certain  stocks  have  a  tendency  to  increase  the  pro- 
portion of  fruit  buds  on  all  kinds  of  canes.  On  the  other  hand,  cool 
summers,  excessive  growth  of  vine  due  to  over  abundance  of  water  or 
nitrogen  in  the  soil  may  cause  buds  in  all  positions  to  be  mostly  sterile. 


—  22  — 

THE    PRINCIPLES   OF    PRUNING.1 

Physiological  Principles. — The  correct  pruning  of  the  vine  is  based 
on  certain  facts  regarding  plant  growth  and  nutrition  which  the  pruner 
should  understand.  Some  of  these  facts  apply  to  all  plants ;  others  are 
peculiar  to  the  vine. 

1.  The  vine  prepares  its  food  by  means  of  the  green  coloring  matter 
(chlorophyll)  of  its  leaves.  All  the  sugar,  starch  and  other  substances 
which  make  up  the  body  of  the  vine  and  of  its  crop  are  elaborated  in 
the  leaves  by  means  of  the  chlorophyll  under  the  influence  of  sunlight. 
The  carbonic  acid  of  the  air  and  the  water  from  the  soil  furnish  the 
main  bulk,  while  the  mineral  salts  from  the  soil  furnish  a  smaller  but 
equally  necessary  part.  A  certain  area  of  green  leaf  surface  function- 
ing for  a  certain  time  is  necessary  to  produce  sufficient  nourishment  for 
the  vital  needs  of  the  vine  and  for  the  production  of  the  crop.  Those 
leaves  most  exposed  to  the  direct  rays  of  the  sun  are  most  active  in 
absorbing  and  producing  food.  The  youngest  leaves  take  all  their 
nourishment  from  the  older  parts  of  the  plant;  somewhat  older  leaves 
use  up  more  nutrient  material  than  they  absorb  from  the  air.  A  young 
shoot  may  thus  be  looked  on  as,  in  a  sense,  parasitic  upon  the  rest  of 
the  vine.  After  a  certain  stage,  the  leaves  produce  more  food  material 
than  they  utilize,  and  the  excess  goes  to  support  other  parts.  The  true 
feeders  of  the  vine  and  of  its  crop,  therefore,  are  the  mature,  dark 
green  leaves. 

This  principle  shows  that  any  method  which  forces  an  unnecessary 
growth  of  young  shoots  or  removes  mature  leaves,  while  still  active, 
limits  the  possibilities  cf  production  and  if  carried  too  far  may  result 
in  starvation  of  the  vine. 

2.  Within  certain  limits  the  tendency  to  fruitfulness  of  a  vine  or  a 
part  of  a  vine  is  inversely  proportionate  to  its  vegetative  vigor.  Within 
these  limits,  methods  which  increase  the  vegetative  vigor  diminish  bear- 
ing, and,  vice  versa,  methods  wrhich  diminish  vigor  increase  bearing. 
Failure  to  reckon  with  this  fact  and  to  maintain  a  proper  mean  between 
the  two  extremes  lead,  on  the  one  hand,  to  comparatively  sterility  and, 
on  the  other,  to  over-bearing  and  premature  exhaustion  of  the  vine. 

The  correct  treatment  of  a  vine  is  that  which  invigorates  it  as  much 
as  is  possible  without  diminishing  the  crop. 

3.  Other  conditions  being  equal,  an  excess  of  foliage  is  accompanied 
by  a  small  amount  of  fruit;  an  excess  of  fruit  by  diminished  foliage. 
This  and  No.  4  are  corollaries  of  Principle  No.  2. 

4.  Bending,  twisting  or  otherwise  injuring  the  tissues  of  the  vines 
or  of  its  parts  tend  to  diminish  its  vegetative  vigor  and,  therefore,  unless 
excessive,  to  increase  its  fruitfulness. 


JThe   second'  part  of  this  bulletin,   entitled   "The  Practice  of  Pruning,"   is  prepared 
and  will  be  published  shortly. 


—  23  — 

5.  The  vine  tends  to  force  out  terminal  buds  and  to  expend  most  of 
its  energy  on  the  shoots  farthest  from  the  trunk.  To  keep  the  vine 
within  practical  limits,  this  tendency  must  be  controlled  by  the  removal 
of  terminal  buds  or  by  measures  which  check  the  flow  of  sap  and  force 
the  growth  of  buds  nearer  the  stock. 

Certain  defective  styles  of  pruning  fail  to  recognize  this  tendency  and 
are,  therefore,  impracticable  and  can  not  be  continued  indefinitely. 
One  of  the  commonest  of  these  is  the  tying  of  fruit  canes  vertically  to 
a  stake. 

6.  The  nearer  a  shoot  or  cane  approaches  the  vertical  the  more  vig- 
orous it  will  be. 

This  principle  is  made  use  of  in  the  Guyot  and  similar  systems  of 
pruning.  The  shoots  from  renewal  spurs  are  tied  up  vertically  to  a 
stake  and  are  thus  rendered  vigorous.  On  the  other  hand,  the  fruit 
canes  are  tied  horizontally  to  wires,  thus  moderating  the  vigor  and 
increasing  fruitfulness. 

7.  The  size  of  vines  or  parts  of  vines  are  inversely  as  their  number, 
if  other  conditions  remain  the  same. 

Thus,  for  example,  the  fewer  vines  to  the  acre,  the  larger  eah  will 
grow;  the  fewer  shoots  allowed  to  grow  on  a  vine  or  the  arm  of  a  vine 
the  larger  each  individual  shoot.  This  principle  extends  to  the  fruit. 
If  we  want  large  bunches  we  must  limit  their  number ;  if  we  want  large 
berries  there  must  not  be  too  many  on  a  bunch. 

Winter  Pruning. — The  principal  pruning  of  the  vine  is  done  while 
the  plant  is  dormant,  between  the  fall  of  the  leaves  at  the  beginning  of 
winter  and  the  starting  of  the  buds  at  the  beginning  of  spring.  In 
large  vineyards  the  pruning  may  have  to  be  spread  over  most  of  this 
period ;  in  smaller  vineyards  it  is  usually  possible  to  prune  in  the  month 
which  is  judged  most  favorable. 

Season. — In  deciding  on  the  best  time  for  pruning  we  must  consider 
the  convenience  of  other  cultural  operations  and  the  effect  of  the  period 
on  the  health  and  bearing  of  the  vine. 

For  convenience,  the  earlier  the  pruning  is  done  the  better.  Pruning 
in  November  or  December  gives  abundant  time  to  gather  and  to  remove 
the  prunings,  to  apply  fertilizers,  to  plow,  irrigate  and  sucker  and  to 
tie  up  the  fruit  canes  before  the  starting  of  the  buds. 

The  effects  of  the  time  of  pruning  on  the  vigor  and  fruitfulness  of 
the  vine  bear  a  close  relation  to  the  location  and  amount  of  reserve 
food  material  in  the  various  parts  of  the  plant. 

During  the  summer  the  leaves  feed  the  canes,  trunk  and  roots.  Just 
before  the  natural  fall  of  the  leaves  the  canes  contain  the  maximum 
amount  of  food  material,  viz,  starch,  sugar,  cellulose  and  other  carbo- 
hydrates. For  two  or  three  weeks,  immediately  following  the  fall  of 
the   leaves   much   of   these   substances   passes   rapidly   downwards   to 


—  24  — 

accumulate  as  reserves  in  the  roots.  Later  these  reserves  ascend  again 
slowly,  to  supply  the  above  ground  portions  of  the  vine  which,  thougn 
dormant,  still  require  nutrition.  In  spring,  during  the  period  just 
before  and  just  after  the  starting  of  the  buds,  this  upward  migration 
of  reserves  is  more  rapid  and  continues  until  the  young  leaves  are  suffi- 
ciently developed  to  supply  the  vine  with  its  carbohydrate  food.1 

If  we  prune  a  vine,  therefore,  immediately  after  the  fall  of  the  leaves 
the  cuttings  contain  the  largest  amount  of  reserves  and  are  in  the  best 
condition  for  use  for  grafting  or  planting.  Three  or  four  weeks  later 
the  roots  contain  the  largest  amount  of  reserves,  and  if  pruning  is  done 
then  they  will  be  in  the  best  condition  to  promote  a  vigorous  growth  in 
the  spring.  When  the  buds  start  in  the  spring,  the  root  has  lost  some  of 
its  reserves,  used  up  by  the  canes  during  the  winter.  Pruning  at  this 
time,  therefore,  results  in  a  less  vigorous  growth  of  shoots,  but  also, 
usually,  in  a  better  "setting"  of  the  crop. 

The  effects  of  the  time  of  pruning  on  the  vigor  and  crop  of  the  vine 
have  been  investigated  by  Professor  Ravaz2  in  a  series  of  experiments 
extending  over  seven  years  with  results  which  have  been  in  the  main 
corroborated  by  tests  at  Davis  of  shorter  duration. 

Vines  pruned  immediately  after  the  fall  of  the  leaves  were  the  earliest 
to  start  in  the  spring.  Those  pruned  when  the  vines  were  most  dormant 
(end  of  December  and  beginning  of  January)  started  on  the  average 
four  days  later.  Those  pruned  at  the  time  pruned  vines  commence  to 
bleed  (about  February  20th  in  the  south  of  France)  started  about  six 
days  later.  Pruning  when  the  terminal  buds  commenced  to  swell 
(March)  retarded  the  lower  buds  eleven  days,  and,  when  the  terminal 
buds  had  grown  two  or  three  inches,  twenty  days. 

The  starting  of  the  buds  was  late,  therefore,  in  proportion  to  the 
lateness  of  the  pruning.  One  exception,  however,  was  noticed.  Vines 
pruned  soon  after  the  vintage  and  while  still  covered  with  green  leaves 
started  on  the  average  ten  days  later  than  those  pruned  after  the  fall 
of  the  leaves. 

The  retardation  of  the  starting  of  the  shoots  in  the  spring  may  be  a 
valuable  means  of  escaping  tl:*  injurious  effects  of  spring  frosts.  In 
one  of  our  tests,  the  crop  on  niiit  rows  pruned  March  13th  was  saved, 
while  that  of  twelve  rows  pruned  November  19th  and  December  21st 
was  completely  ruined  by  a  frost  on  April  21st.  Late  pruning  also 
retards  the  blossoming  though  somewhat  less  than  it  does  the  starting. 
Pruning  as  late  as  March  may  retard  the  blossoming  ten  days.  The 
time  of  ripening  is  also  influenced  slightly  in  the  same  direction.  When 
spring  frosts  occur,  this  influence  appears  to  be  reversed.  The  vines 
pruned  early  may  blossom  and  ripen  their  fruit  later.     This  is  because 


aVidal,  J.  L.   "Les  reserves  de  la  Vigne."      Revue  de  Viticulture  I,  pp.  895  to  903. 
2Ravaz,  L.     "Taille  hative  ou  Taille  tardive,"  1912. 


—  25  — 

the  frost  having  destroyed  the  first  shoots,  the  only  flowers  and  fruit 
which  appear  are  on  buds  which  have  started  after  the  frost. 

Vines  pruned  before  the  fall  of  the  leaves  are  weakened.  Otherwise 
the  time  of  winter  pruning  has  little  direct  effect  on  the  vigor  of  the 
vines.  Professor  Ravaz  notes  somewhat  greater  vigor  in  vines  pruned 
earliest  in  the  dormant  season.  On  these  vines  the  crop  was  diminished 
by  frost.  The  extra  vigor  was  due,  therefore,  probably  not  to  the  time 
of  pruning  but  to  the  lack  of  crop. 

Late  pruned  vines  gave  on  the  average  larger  crops.  Professor  Ravaz 
accounts  for  this  by  their  escape  from  frost.  The  later  blossoming 
may  also  be  a  factor.  At  Davis,  Muscat  vines  pruned  in  the  middle  of 
April  produced  22.6  pounds  per  vine,  while  vines  pruned  in  December 
produced  only  10.1  pounds,  with  no  injury  from  frost  in  either  case. 

Pruning  may  be  done,  therefore,  in  frostless  locations  and  with 
varieties  which  set  their  fruit  well,  at  any  time  when  the  vines  are 
without  leaves.  Where  spring  frosts  are  common  the  pruning  should 
be  as  near  the  time  of  the  swelling  of  the  buds  as  possible.  The  benefits 
of  late  pruning  without  its  inconveniences  can  be  obtained  by  the  system 
of  ' '  double  * '  or  "  clean ' '  pruning  practiced  in  some  regions.  This  may 
be  applied  in  various  ways.  The  simplest  is  to  shear  off  all  the  canes 
to  a  length  of  15  to  18  inches  at  any  time  during  the  winter  that  is 
convenient.  This  permits  plowing  and  other  cultural  operations,  and 
the  final  pruning  is  done  in  April.  A  better  method  is  to  prune  the 
vines  as  usual  but  to  leave  the  spurs  with  four  or  five  extra  buds. 
These  spurs  are  then  shortened  back  to  the  proper  length  as  late  as 
practicable.  In  some  cases  the  method  practiced  in  the  Medoc  may  be 
used.  This  consists  in  leaving  a  foot  or  fifteen  inches  of  cane  beyond 
the  last  bud  needed  and  removing  all  the  extra  buds  at  the  time  of  prun- 
ing. The  base  buds  are  said  to  be  retarded  by  the  length  of  cane  above 
them  the  presence  of  buds  on  the  cane  having  no  effect. 

Early  pruning  (December)  promotes  the  vigor  of  the  vine  and  results 
in  early  starting  of  the  buds.  Late  pruning  (March,  April)  promotes 
fruiting,  may  slightly  weaken  the  vines  and  results  in  late  starting  of 
the  buds.  Weak  vines,  those  which  have  borne  too  much  or  which  have 
been  injured  by  insects  or  diseases  are  better  pruned  early.  Very  vig- 
orous vines,  especially  in  frosty  locations,  should  be  pruned  late. 

Amount  of  Pruning. — An  average  vine  before  pruning  may  have 
twenty-five  canes  with  an  average  of  fifteen  buds  on  each  or  three 
hundred  and  seventy-five  buds  in  all.  If  the  vine  is  not  pruned,  all 
these  buds  will  not  start  or  produce  shoots.  Probably  not  more  than 
fifty  or  one  hundred  will  do  so.  If  we  pruned  the  canes  back  so  that 
we  leave  only  fifty  or  one  hundred  buds  the  same  number  of  shoots  will 
be  produced.  The  only  effect  will  be  that  buds  nearer  the  bases  of  the 
canes  will  start  instead  of  buds  near  the  ends.  (See  Physiological 
Principle  No.  5,  page  25.)  The  quality  and  quantity  of  the  crop  and 
the  vigor  of  the  vine  and  its  shoots  will  be  influenced  little,  if  at  all. 


—  26  — 

If  we  prune  the  vine  more  severely  and  leave  only  half  this  number 
of  buds,  a  smaller  number  of  shoots  will  be  produced.  As  this  smaller 
number  has  the  same  store  of  reserve  material  in  trunk  and  root  to 
draw  on  and  the  same  root  system  to  supply  water  and  soil  nutrients, 
each  shoot  will  grow  larger  and  more  vigorously.  (See  Principle  No.  7, 
page  25.)  This  smaller  number  of  large  shoots  will  produce  as  much 
foliage  as  the  larger  number  of  small  shoots  on  the  unpruned  vine  and 
the  vigor  of  the  vine  is  therefore  not  diminished. 

There  will  also  be  a  smaller  number  of  bunches  produced,  but  each 
of  these  will  be  larger  and  have  larger  berries  so  that  the  total  weight 
of  crop  will  be  as  large  as  on  an  unpruned  vine.  In  fact,  the  weight 
of  crop  will  probably  be  larger,  as  it  is  easier  for  the  vine  to  supply  the 
water  and  sugar  which  constitute  the  main  bulk  of  large  berries  than 
the  stems,  seeds  and  skin  which  form  a  larger  part  of  small  berries. 

We  can  increase  the  severity  of  the  pruning,  that  is,  diminish  the 
number  of  buds  left,  still  further,  without  materially  influencing  either 
the  vigor  of  the  vine,  the  amount  of  foliage  or  the  weight  of  crop. 
Beyond  a  certain  point,  however,  the  crop  is  diminished.  There  are 
two  causes  for  this.  One  is  that  there  is  a  certain  maximum  size  for 
the  bunches  and  berries  of  any  particular  vine.  When  we  have  reached 
this  maximum,  any  further  decrease  of  fruit  bunches  results  in  a 
diminished  crop.  The  other  is  that  the  excessive  vigor  given  to  the 
shoots  is  unfavorable  to  fruiting  (see  Physiological  Principle  No.  2, 
page  24),  often  causing  "coulure"  or  dropping  of  the  blossoms  without 
"setting."  The  primer  should  endeavor,  therefore,  to  leave  just 
enough  fruit  buds  to  furnish  the  number  of  bunches  that  the  vine  can 
bring  to  perfection. 

Beyond  this  point  the  crop  is  diminished  and  the  vigor  of  the  vine 
correspondingly  increased.  If  we  prune  the  vine  so  severely  that  no 
crop  is  produced,  the  vigor  of  the  vine  attains  its  maximum.  Even 
though  we  prune  off  all  the  growth  of  the  season  the  vine  is  not  weak- 
ened, as  it  produces  shoots  from  dormant  and  adventitious  buds  with 
so  much  facility  that  the  foliage  produced  is  as  great  as  when  we  leave 
spurs  with  well  formed  buds. 

Heavy  winter  pruning,  therefore,  invigorates  the  vine  by  diminishing 
the  crop.  Light  winter  pruning  increases  the  crop.  If  this  increase 
is  represented  by  a  larger  number  of  bunches  than  the  vine  can  properly 
nourish,  the  crop  will  be  inferior  in  quality  and  the  vine  weakened  by 
overbearing.  On  a  mature  vine  of  normal  vigor,  the  primer  should 
leave  the  same  number  of  spurs  and  fruit  buds  as  were  left  the  year 
before.  If  the  vine  appears  abnormally  vigorous  more  fruit  buds  should 
be  left  in  order  to  utilize  this  vigor  in  the  production  of  crop.  On  the 
other  hand,  if  the  vine  appears  weak  it  should  be  pruned  more  severely 


—  27  — 

than  the  previous  year,  that  is,  fewer  fruit  buds  should  be  left,  in  order 
to  strengthen  the  vine  by  diverting  its  activities  from  crop  production 
into  building  up  tissues  and  replenishing  its  store  of  reserve  food 
materials.  Any  attempt  to  make  a  weak  vine  bear  a  normal  crop  can 
succeed  only  in  further  weakening  of  the  vine  and  in  the  production  of 
inferior  grapes.  By  pruning  such  a  vine  for  a  small  crop,  the  grapes 
obtained  will  be  of  good  quality  and  the  vine  invigorated  so  that  it  can 
produce  normal  crops  in  subsequent  years. 

These  arguments  apply  not  only  to  individual  vines,  but  to  indi- 
vidual arms  or  canes  of  a  vine.  The  number  of  fruit  canes,  spurs  or 
buds  should  be  in  proportion  to  the  strength  of  the  arm.  A  fruit  cane 
or  fruit  spur  should  be  the  longer  the  more  vigorous  it  is. 

The  vigor  of  a  vine  is  determined  not  only  by  the  growth  it  has  made 
but  by  the  amount  of  reserves  contained  in  its  canes  and  body.  Its 
condition  in  this  respect  can  be  determined  by  an  inspection  of  the 
canes.  These  should  be  firm  and  heavy.  Soft,  pithy  canes  indicate 
weakness  and  should  never  be  left  for  fruit  canes.  If  all  or  most  of 
the  canes  on  a  vine  are  of  this  character  the  vine  should  be  pruned  very 
short ;  in  extreme  cases,  sufficiently  short  to  prevent  any  attempt  to  bear. 
On  the  other  hand,  long,  firm  canes  should  be  made  to  produce  fruit  by 
being  left  longer  whether  as  fruit  spurs  or  fruit  canes. 

The  iodine  test  is  useful  in  determining  the  condition  of  canes  or 
vines  in  respect  to  reserves.  For  this  test  a  solution  of  iodine  in  75 
per  cent  alcohol  is  used — 100  parts  by  weight  of  alcohol  to  one  part  by 
weight  of  iodine. 

A  clean,  slanting  cut  is  made  through  the  cane  and  a  few  drops  of 
the  solution  placed  on  the  cut.  In  three  to  five  minutes  a  well  nourished 
cane,  containing  abundance  of  starch  (reserves)  turns  black  all  over 
the  cut.  An  imperfectly  nourished  cane  will  turn  black  only  on  the 
medullary  rays  which  will  show  like  the  spokes  of  a  wheel.  If  only  a 
few  black  specks  are  produced  by  the  iodine,  reserves  are  lacking.  In 
the  first  case  the  canes  are  good  for  use  as  cuttings  or  grafts  and  indi- 
cate that  the  vine  is  capable  of  producing  a  good  crop.  The  pruning 
should  be  correspondingly  generous.  In  the  last  case  the  cuttings  are 
useless  and  the  vine  should  be  pruned  very  short.  A  few  tests  of  this 
kind  in  a  vineyard  will  give  a  very  fair  idea  of  the  amount  of  reserves 
in  the  vines  and  is  a  valuable  aid  in  determining  the  amount  of  prun- 
ing to  give. 

Young  and  Old  Vines. — During  the  first  part  of  the  life  of  the  vine, 
the  main,  if  not  the  only,  object  of  the  pruner  is  to  develop  a  frame- 
work of  proper  form.  The  methods  of  doing  this  and  the  time  required 
will  depend  on  the  form  aimed  at  and  on  the  more  or  less  favorable 
conditions  for  rapid  growth.  The  crop  during  this  formative  period 
should  be  a  secondary  object.     In  fact,  nothing  is  lost,  if  it  is  left  out 


—  28  — 

of  consideration  altogether  except  in  so  far  as  it  affects  the  attainment 
of  the  desired  form.  Vines  which  are  so  pruned  as  to  reach  most 
rapidly  and  perfectly  a  desirable  shape  will  not  only  bear  more  when 
they  reach  adult  size,  but  will  practically  always  bear  more  fruit  during 
the  formative  period  than  if  the  fruit  alone  were  in  view. 

In  pruning  an  adult  vine,  two  objects  must  be  kept  in  view ;  first,  the 
production  of  the  crop  of  the  current  year,  and  second,  the  maintenance 
of  the  proper  form  of  the  vine.  Each  of  these  objects  is  perhaps  of 
equal  importance.  On  the  attainment  of  the  first  depends  the  current 
crop,  on  that  of  the  second  all  future  crops. 

Units  of  Pruning. — When  a  vine  has  reached  the  stage  of  full  bear- 
ing, pruning  consists  in  leaving  certain  parts  of  the  new  wood  for 
fruiting,  other  parts  for  renewal  or  the  production  of  wood  for  the  next 
year  and  finally  other  parts  for  the  replacing  or  shortening  of  arms. 


Fig.   11. — Unit  of   short  pruning. 

All  new  wood  not  needed  for  these  purposes  and  all  arms  to  be  replaced 
are  removed. 

Whatever  the  system  of  pruning  adopted,  in  all  our  Californian 
systems,  each  arm  of  each  vine  is  treated  by  the  same  method,  modified 
only  by  the  vigor  of  the  individual  cane,  arm  or  vine.  There  are  two 
general  methods  used,  viz,  spur  pruning  and  cane  pruning.  The  treat- 
ment of  a  single  arm  by  either  of  these  methods  may  be  called  the  ' '  unit 
of  pruning." 

The  unit  of  pruning  in  spur  pruning  is  illustrated  in  Fig.  11,  repre- 
senting a  long  arm  about  seven  years  old.  At  the  end  of  the  arm  is 
shown  the  two-eye  spur  ($2)  of  the  previous  year  bearing  two  canes, 
(C  and  Ci).  Near  the  base  of  the  arm  is  shown  a  single  water-sprout 
(WS)  growing  out  of  old  wood.  Such  an  arm  would  normally  bear 
other  canes,  but  as  they  would  all  be  removed  entirely  at  pruning  they 
are  omitted  to  simplify  the  figure. 


—  29  -^ 

In  priming  such  an  arm,  one  of  the  canes  growing  out  of  the  spur  of 
the  previous  year  ($2)  is  cut  back  to  form  a  new  spur  and  the  other 
removed  entirely.  In  deciding  on  which  cane  to  use  for  the  new  spur, 
we  must  choose  one  that  is  suitable  for  fruiting,  viz,  well  ripened,  of 
moderate  thickness  and  with  well  formed  buds.  Of  those  which  fulfill 
this  condition,  we  must  choose  that  which  is  in  the  best  position  to 
preserve  the  form  of  the  vine.  This,  in  most  cases,  will  be  the  lowest 
(C  in  the  figure),  because  it  increases  the  length  of  the  arm  the  least. 
If  the  lowest,  however,  is  weak,  broken  or  otherwise  unsuitable,  we  are 
obliged  to  take  one  higher  up. 

When  a  cane  arising  from  the  base  bud  of  the  spur  of  the  previous 
year  is  chosen  for  the  new  spur,  the  length  of  the  arm  is  lengthened 
imperceptibly.  A  spur  from  the  first  bud  (C)  will  lengthen  it  usually 
little  over  an  inch,  one  from  the  second  bud  (0)  three  or  four  inches. 


Fig.   12. — Unit  of  long  pruning. 


In  any  case,  the  arm  finally  becomes  too  long  like  the  one  in  the  figure. 
It  must  then  be  shortened  or  replaced.  This  can  be  done  by  using  a 
conveniently  placed  water-sprout  for  a  replacing  spur  as  at  R  in  the 
figure,  and  cutting  back  the  arm  in  the  place  indicated  by  the  line  g. 

This  cutting  back  of  an  arm  should  be  deferred  until  the  following 
year  as  the  replacing  spur  will  produce  little  or  no  fruit.  In  the  mean 
while  the  fruit  spur  from  cane  C  will  bear  a  crop  and  the  replacing 
spur  B  will  produce  fruit  wood  for  the  following  year. 

The  cane  chosen  (C)  is  cut  at  a,  1),  or  d,  leaving  a  fruit  spur  of  one, 
two  or  three  fruit  buds  and  the  cane,  Ci,  removed  entirely  by  a  cut  at  /. 
The  more  vigorous  the  variety  and  the  particular  cane,  the  more  buds 


—  30  — 

should  be  left.  The  water-sprout  is  cut  back  at  a,  leaving  a  replacing 
spur  of  one  eye.  Of  course  a  replacing  spur  is  left  only  in  case  the 
arm  is  too  long  and  will  require  shortening  the  next  year. 

The  unit  in  short  pruning  consists  then  of  a  single  fruit  spur  of  one, 
two  or  three  fruit  buds. 

The  unit  of  pruning  in  long  and  half  long  systems  is  shown  in  Fig.  12 
and  consists  of  a  fruit  cane,  F2,  with  its  renewal  spur,  Si. 

In  the  illustration,  #2  represents  the  renewal  spur  of  two  years 
previous.  On  it  was  left  a  fruit  cane  F2,  which  has  produced  the  crop 
of  the  previous  season  and  a  renewal  spur,  Si,  which  has  produced  fruit 
wood  for  the  present  season. 

In  pruning,  the  fruit  cane,  F2,  is  removed  entirely  at  g.  The  upper 
cane,  C,  of  the  renewal  spur,  Si,  is  used  for  a  new  fruit  cane  and  short- 
ened to  about  /  for  half  long  and  to  about  /1  for  long  pruning.  The 
lower  cane,  Ci,  is  cut  back  at  a  to  form  a  renewal  spur,  S,  which  will 
produce  the  new  wood  for  the  next  winter  pruning. 

This  is  the  normal  method  of  procedure,  but  various  modifications  are 
often  necessary.  If  the  cane,  C,  is  unsuitable  on  account  of  lack  of 
vigor,  other  canes  such  as  Ci,  or  even  B,  D,  near  the  base  of  the  old 
fruit  cane,  may  be  used  for  a  new  fruit  cane.  The  essential  point  is 
that  the  cane  used  for  this  purpose  shall  originate  from  two-year-old 
wood.  In  the  same  way,  any  suitably  placed  cane  may  be  used  for  a 
renewal  spur.  Water-sprouts  from  three-year,  four-year  or  older  wood 
being  available  {RP) .  The  essential  point  in  this  case  is  that  the  renewal 
spur  shall  be  below  the  fruit  cane,  that  is,  nearer  the  trunk. 

Replacing  spurs  for  shortening  the  arms  are  occasionally  needed  as 
in  spur  pruning,  but  usually  the  same  spur  can  be  used  both  for  renewal 
and  replacing.  The  water-sprout,  RP,  may  be  used  for  this  purpose, 
cutting  it  at  h  or  b,  according  to  its  vigor. 

Summer  or  Herbaceous  Pruning. — Summer  pruning,  of  which  there 
are  many  forms,  consists  in  the  removal  of  buds,  shoots  or  leaves  while 
they  are  green  or  herbaceous,  and  is  done  therefore  while  the  vine,  is 
growing  or  active. 

Weakening  Effect. — The  effects  of  summer  pruning  are  in  some 
respects  very  different  from  those  of  winter  pruning  and  in  some  quite 
the  opposite.  If  we  remove  a  part  of  a  cane  in  the  winter,  we  do  not 
weaken  the  vine  at  all,  in  fact,  we  may  strengthen  it  indirectly  by 
diminishing  bearing.  If  we  remove  a  growing  cane  in  the  summer,  on 
the  contrary,  we  weaken  the  vine  because  we  remove  leaves  which  are 
its  principal  feeding  organs  and  to  which  it  owes  its  vigor.  See  Prin- 
ciple No.  1,  page  24. 

This  weakening  effect  is  greatest  in  the  middle  of  summer  when  the 
vine  is  most  active  and  most  in  need  of  the  food  supplied  by  the  leaves. 


—  31  — 

The  removal  of  all  the  leaves  by  defoliating  insects  at  this  time  may 
kill  the  vine.  It  is  not  so  great  early  in  the  spring,  when  we  can  remove 
a  certain  number  of  small  shoots  without  serious  injury.  In  fact,  vines 
struck  by  spring  frosts  are  often  more  vigorous  the  following  year 
because  the  weakness  due  to  removal  of  leaves  is  more  than  counter- 
balanced by  the  strengthening  due  to  lack  of  crop.  It  is  least  harmful 
late  in  the  autumn  after  the  canes  have  matured  and  the  leaves  com- 
mence to  turn  yellow. 

Concentrating  Effect. — The  removal  of  growing  shoots  or  parts  of 
shoots  has  also  an  effect  similar  to  that  of  winter  pruning,  viz,  the  con- 
centration of  the  growth  of  the  vine  on  the  parts  which  remain.  This 
concentrating  effect  and  the  weakening  effect  occur  in  inverse  ratio  and 
vary  according  to  the  time  and  method  of  operation.  In  early  spring, 
at  the  starting  of  the  shoots,  the  weakening  effect  is  very  slight  and  the 
concentrating  effect  almost  as  marked  as  that  of  winter  pruning.  In 
early  summer,  with  the  vines  in  full  growth,  the  weakening  effect  may 
be  sufficient  to  completely  neutralize  the  concentrating  effect,  i.  e.,  the 
removal  of  some  of  the  shoots  may  so  weaken  the  vine  that  there  will  be 
no  increase  of  growth  in  those  which  are  left.  Still  later  the  weaken- 
ing effect  may  exceed  the  concentrating  effect,  i.  e.,  the  shoots  which  are 
left  will  make  less  growth  than  if  none  had  been  removed. 

Uses  of  Summer  Pruning. — Summer  pruning  has  various  uses,  of 
which  the  principal  are : 

1.  To  direct  the  growth  into  useful  parts  of  the  vine :  disbudding, 
thinning  of  shoots  and  topping  of  young  vines;  suckering;  water- 
sprouting. 

2.  To  moderate  the  vigor  of  the  vine  and  so  increase  its  bearing: 
pinching,  topping. 

3.  To  increase  the  size  of  fruit  (at  expense  of  sweetness)  :  topping. 

4.  To  increase  the  shade  on  the  fruit:  topping  or  pinching  to  pro- 
mote upright  position  of  shoots  and  growth  of  laterals. 

5.  To  decrease  the  shade  on  the  fruit :  defoliating. 

Three  other  operations  performed  in  the  summer  may  be  considered 
as  forms  of  summer  pruning,  viz: 

6.  Thinning  of  the  fruit. 

7.  Ringing. 

8.  Removal  of  scion  and  surface  roots. 

Disbudding  is  practiced  on  young  vines  during  the  second  and  third 
years.  It  consists  in  removing  the  buds  on  the  lower  part  of  the  stem 
of  the  vine  in  order  to  concentrate  the  growth  in  the  shoots  above  and 
to  avoid  the  production  of  canes  low  down  where  they  would  have  to  be 
cut  off  later.  The  buds  are  not  removed  until  they  have  grown  an 
inch  or  two.     Many   of  them   are   dormant   or   adventitious   and   the 


—  32  — 

attempt  to  remove  them  earlier  would  make  it  necessary  to  go  over  the 
vineyard  too  often.  The  sooner  they  are  removed,  however,  the  better, 
before  they  have  used  up  much  of  the  reserves  of  the  vine  and  when  the 
concentrating  effect  of  their  removal  is  at  its  maximum.  On  younger 
vines  which  have  not  yet  formed  a  stem,  it  consists  in  removing  all  the 
buds  but  one  in  order  to  concentrate  all  the  growth  into  a  single  shoot 
from  which  the  following  year  the  stem  will  be  formed. 

Thinning  of  Shoots. — The  purpose  of  this  operation  is  the  same  as 
that  of  disbudding.  It  is  done  after  the  shoots  have  grown  several 
inches  or  more.  It  is  inferior  to  early  disbudding  as  it  is  more  weaken- 
ing to  the  vine  and  the  concentrating  effect  is  correspondingly  less.  It 
is  simpler  than  disbudding,  as  it  necessitates  going  over  the  vineyard 
only  once.  It  is  used  principally  during  the  second  year  for  vines 
which  have  been  cut  back  to  two  buds  at  the  end  of  the  first  season's 
growth. 

Topping  the  Young  Vines. — When  by  disbudding  or  thinning  of  shoots 
during  the  second  year,  all  the  growth  has  been  concentrated  into  a 
single  shoot,  this  shoot  will  grow  with  great  vigor.  "When  it  has  grown 
about  twelve  inches  above  the  top  of  the  stake,  that  is,  above  the  height 
at  which  it  is  intended  to  develop  the  head,  it  should  be  topped.  This 
topping  has  the  effect  of  forcing  the  growth  of  laterals.  These  laterals 
can  be  used  at  the  following  winter  pruning  as  fruit  spurs  and  as  the 
commencement  of  permanent  arms.  If  this  topping  is  not  done,  there 
may  be  very  few  buds  on  the  cane  when  mature  at  the  height  at  which 
it  is  desired  to  make  a  head.  It  will,  therefore,  be  difficult  to  find  buds 
in  the  proper  place  for  the  development  of  the  arms  and  to  produce  the 
crop  of  grapes  which  the  vine  should  yield  the  third  year. 

During  the  third  summer,  the  number  of  shoots  will  be  small  for  the 
vigor  of  the  young  vine.  They  will  grow  rapidly  and  be  very  liable  to 
be  broken  off  by  the  wind  while  tender  and  succulent.  If  topped  before 
they  are  long  enough  to  afford  sufficient  leverage  to  the  force  of  the 
wind,  they  will  have  time  to  lignify  their  tissues  and  become  tough 
enough  to  withstand  the  pressure  of  the  wind.  Topping  at  this  time 
helps  to  keep  the  shoots  upright  and  makes  it  easier  to  give  the  arms 
the  proper  direction  at  the  following  winter  pruning. 

Suckering. — This  is  the  removal  of  all  shoots  which  originate  at  or 
below  the  surface  of  the  ground.  Neglect  of  suckering  results  in 
diminished  vigor  of  the  whole  above  ground  portion  of  the  vine.  The 
suckers  bear  little  or  no  fruit,  hence  growing  vigorously,  they  appro- 
priate the  sap  which  should  nourish  the  whole  vine.  Finally,  the  top 
may  die,  the  whole  growth  go  into  the  suckers,  and  all  the  benefits  of 
a  properly  shaped  vine  will  be  lost.  Such  a  vine  can  be  renovated 
only  by  cutting  off  the  old  stump  and  building  up  a  new  vine  from  a 
vigorous  sucker. 


—  33  — 

With  grafted  vines,  the  consequences  are  even  more  serious.  The 
suckers,  coming  from  the  stock,  take  the  sap  even  more  easily  from  the 
top  which  is  connected  to  the  root  by  the  union  which  impedes  some- 
what the  passage  of  water  and  food  materials.  A  grafted  vine  which 
has  been  seriously  weakened  by  the  prolonged  growth  of  suckers  is 
useless  and  can  not  be  renovated. 

Suckering  should  be  done  with  the  greatest  care  and  thoroughness 
during  the  first  four  or  five  years.  This  will  save  a  great  deal  of 
expensive  and  troublesome  work  later.  Very  few  suckers  will  be  pro- 
duced by  vines  which  have  been  properly  cared  for  in  this  respect  dur- 
ing the  first  three  years  and  such  vines  will  usually  cease  to  produce 
any  after  five  or  six  years.  Vines  on  which  the  suckering  has  been 
imperfectly  done  during  the  first  three  years,  on  the  contrary,  will 
always  produce  an  abundant  crop  of  underground  shoots  every  year. 

Suckering,  like  disbudding,  should  be  done  as  early  in  the  season  as 
possible  for  the  reasons  already  given.  Another  and  even  more  impor- 
tant reason  is  that  suckers  which  are  removed  late,  and  especially  those 
which  are  allowed  to  grow  the  whole  summer,  promote  the  formation 
of  dormant  buds  and  of  tissue  which  readily  forms  adventitious  buds 
below  ground. 

It  is  necessary  to  sucker  young  vines  two  or  three  times  during  the 
spring.  This  is  done  every  time  the  vines  are  visited  for  hoeing  or 
tying  up.  When  the  suckers  are  soft  and  succulent  they  are  easily 
pulled  off  without  cutting.  They  must  be  removed  completely  from  the 
base.  When  they  get  a  little  tough  it  is  necessary  to  dig  down  to  their 
point  of  origin  for  this  purpose.  It  is  worse  than  useless  to  remove  a 
sucker  partially.  The  part  which  remains  forms  an  underground  spur 
or  arm  which  will  be  a  source  of  perennial  trouble. 

Water-sprouting. — This  is  the  removal  of  sterile  shoots.  When  it  is 
done  to  prevent  growth  in  places  where  growth  is  not  wanted,  or  to 
concentrate  growth  in  parts  where  it  is  wanted,  it  is  advisable.  The 
removal  of  all  sterile  shoots  in  all  cases  on  the  theory  that  they  are 
useless,  however,  is  mistaken  practice. 

The  growth  of  a  large  number  of  water-sprouts  is  usually  a  sign  that 
the  full  vigor  of  the  vine  is  not  being  used  for  the  production  of  crop. 
The  cure  for  this  is  longer  or  a  different  style  of  winter  pruning.  The 
production  of  sterile  shoots  on  what  ought  to  be  fruit  wood  often  indi- 
cates some  cultural  error,  such  as  excess  of  water,  nitrogen  or  humus, 
too  late  growth  of  the  vine  in  autumn  or  excessive  vigor. 

Water-sprouts  may  be  removed  with  good  results  in  certain  cases.  If 
the  vines  are  weak,  the  growth  may  by  this  means  be  concentrated  in 
the  bearing  shoots  which  will  thus  be  able  to  nourish  their  crop  better. 
In  this  case  the  water-sprouts  must  be  removed  early,  before  they  have 
grown  more  than  a  few  inches.  Otherwise,  the  vine  will  be  still  further 
3— BUL241 


—  34  — 

weakened,  and  the  trouble  increased  the  following  year.  If  the  vines 
are  excessively  vigorous,  diminishing  the  foliage  by  the  late  removal  of 
water-sprouts  may  correct  this  defect.  It  is  more  reasonable,  however, 
to  utilize  this  vigor  for  crop  production  by  a  change  in  the  winter  prun- 
ing. Water-sprouts  are  sometimes  troublesome  by  growing  through  the 
bunches,  making  it  impossible  to  gather  the  crop  without  injury.  This 
is  particularly  harmful  with  shipping  grapes.  Where  much  of  tlr's 
trouble  exists,  it  indicates  that  the  vine  has  an  unsuitable  shape.  This 
can  be  modified  in  the  winter  pruning  by  spreading  the  vine  sufficiently 
to  allow  all  the  bunches  to  hang  free. 

Sterile  shoots  are  by  no  means  completely  useless.  The  foliage  they 
produce  nourishes  the  vine  and  makes  it  more  capable  of  bearing  fruit. 
They  are  needed  for  use  as  renewal  and  replacing  spurs,  for  which  pur- 
pose they  are  better  than  fruitful  shoots,  being  more  vigorous. 

Pinching. — This  consists  of  the  removal  of  the  growing  tip  of  a  shoot 
with  thumb  and  finger.  Its  weakening  effect  is  very  slight,  as  no 
expanded  leaves  and  a  very  small  amount  of  material  are  sacrificed. 

Its  immediate  effect  is  to  arrest  the  elongation  of  the  shoot.  If  this 
is  done  when  the  shoot  is  15  inches  to  18  inches  long  the  shoot  has  time 
to  become  tough  enough  to  resist  the  wind  before  it  gets  long  enough  to 
afford  the  wind  much  pressure  surface.  Shoots  pinched  as  early  as  this 
usually  produce  a  new  growing  tip  from  a  lateral  which  later  can  not  be 
distinguished  from  an  original  growing  tip.  Later  pinching  usually 
causes  the  growth  of  several  strong  laterals. 

Pinching  fruit  shoots,  just  before  blossoming,  tends  to  make  the  fruit 
"set"  better.  It  is,  therefore,  a  remedy  for  "coulure."  Pinching  the 
first  shoots  on  a  fruit  cane  tends  to  promote  the  starting  of  other  buds, 
and  therefore  the  production  of  more  bunches.  By  pinching  we  can 
accomplish  most  of  the  objects  of  topping  with  a  minimum  weakening 
effect  on  the  vine.  Figure  9  shows  a  fruiting  shoot  at  the  proper  stage 
for  the  first  pinching. 

Topping. — This  consists  in  removing  one,  two,  or  more  feet  of  the  end 
of  a  growing  shoot,  usually  in  June  and  July  or  later.  In  some  regions 
topping  is  practiced  regularly  twice  or  even  three  times  during  the 
season.  In  general,  it  is  more  used  in  the  cooler  districts  than  in  the 
hotter. 

If  practiced  early,  it  has  much  the  same  effect  as  pinching.  It  tends 
to  keep  the  canes  upright  and  to  cause  the  development  of  laterals.  It 
involves  the  removal  of  leaves  and  is  therefore  weakening,  which  may. 
be  an  advantage  with  extra  vigorous  vines.  In  very  windy  districts  it 
is  necessary  to  prevent  the  shoots  being  broken  off  entirely  by  the  wind. 
The  later  the  topping  is  done  the  more  leaves  are  removed  and  the  more 
weakening  the  practice  is  to  the  vine.  Constant  severe  topping  may 
have  a  serious  effect  on  the  vigor  of  even  the  strongest  vines. 


—  35  — 

In  general,  topping  tends  to  increase  the  size  of  the  grapes  and  to 
decrease  their  quality.  For  table  grapes  on  vigorous  vines  it  is  some- 
times an  advantage  if  not  carried  too  far.  At  least,  three  or  four  leaves 
should  be  left  above  the  fruit  when  the  topping  is  done  early,  and  seven 
or  eight  when  the  topping  is  done  late.  For  wine  or  raisin  grapes  it  is 
seldom  advisable  as  it  decreases  the  sugar  and  flavor  of  the  grapes. 
With  long  pruned  vines,  especially  when  trellised,  it  is  often  possible  to 
obtain  the  benefits  of  the  practice  without  its  defects  by  topping  only 
the  shoots  on  the  fruit  canes  and  allowing  the  shoots  on  the  replacing 
spurs  to  grow  normally. 

Both  pinching  and  topping  are  used  frequently  with  the  object  of 
protecting  the  fruit  from  sunburn  by  increasing  the  shade  on  the 
grapes.     For  this  purpose  pinching  is  much  superior  to  topping. 

"When  a  shoot  is  allowed  to  grow  without  interference,  it  takes  at  first 
a  more  or  less  upright  direction.  As  it  increases  in  length,  the  weight 
of  the  shoot  tends  to  bend  it  over  to  a  more  or  less  horizontal  or  down- 
ward direction.  With  some  rapidly  elongating  varieties,  the  shoots 
bend  over  and  take  a  reclining  position,  resting  for  a  considerable  por- 
tion of  their  length  on  the  soil.  With  nearly  all  varieties  they  will 
finally  bend  outwards  and  downwards  sufficiently  to  open  up  the  center 
of  the  vine  to  the  sun. 

In  many  cases,  this  opening  up  of  the  center  is  an  advantage,  promot- 
ing the  coloring  of  the  grapes  and  the  control  of  mildew.  In  some,  it 
encourages  sunburn  of  the  grapes.  Sunburn,  however,  is  not  due  alone 
to  the  direct  rays  of  the  sun.  This  is  proved  by  the  fact  that  some 
bunches  completely  exposed  do  not  sunburn  and  others  much  shaded  do. 
Sunburn  occurs  in  vineyards  where  the  shade  temperature  seldom  goes 
above  100°  F.  and  may  not  occur  in  others  where  it  often  rises  to  110°  F. 

The  commonest  form  of  sunburn  is  due  to  an  excess  of  evaporation 
over  sap  supply.  If  more  water  is  lost  through  the  skin  of  the  grape 
than  is  supplied  through  the  stem,  it  will  dry  up.  An  excess  or  a 
deficiency  of  water  in  the  soil  may  curtail  the  sap  supply  and  sunburn 
result.  Defective  or  diseased  roots,  wounds  or  fungus  in  stem  or  arms, 
may  have  the  same  effect.  Increasing  the  shade,  therefore,  is  merely  a 
palliative,  and  any  method  which  weakens  the  vine  will  increase  the 
trouble. 

If  we  pinch  the  growing  shoots  once  or  twice  before  they  are  three 
feet  long  we  increase  the  shade  in  two  ways.  First,  they  grow  more 
upright  as  they  are  relieved  from  the  weight  of  the  growing  top  until 
they  are  sufficiently  lignified  to  retain  their  upright  position.  Second, 
they  produce  laterals  which  increase  the  number  of  leaves  near  their 
bases  and  over  the  head  of  the  vine.  Topping  being  done  later  is  less 
effective  in  these  respects,  and  moreover,  involving  the  removal  of  feed- 
ing leaves,  may  weaken  the  vine  so  much  as  to  increase  the  trouble. 


—  36  — 


A  B 

Fig  13. — Bunch  of  green  grapes  before  (A)   and  after   (B)   thinning. 


—  37  — 

Defoliating. — The  development  of  the  color  of  the  grapes  is  influenced 
more  by  the  light  than  by  the  heat  of  the  sun.  The  coloring  of  Tokay 
grapes  can  sometimes  be  facilitated  in  the  cooler  districts  by  means 
which  expose  the  bunches  to  more  sunlight.  One  of  these  means  is  the 
removal  of  leaves.  This  of  course  will  tend  to  weaken  the  vine.  If 
the  vines  are  excessively  vigorous,  this  may  not  be  a  disadvantage.  If 
only  the  leaves  in  the  center  of  the  vine,  which  have  already  commenced 
to  turn  yellow,  are  removed,  the  weakening  effect  may  be  very  slight. 
Better  insolation,  however,  can  usually  be  obtained  more  profitably  by 
changing  the  form  of  the  vine  or  by  thinning  the  bunches. 

Removal  of  the  interior  leaves  may  be  useful  in  some  cases,  with  very 
late  varieties,  to  protect  them  from  molding  after  rains.  It  allows  sun 
and  air  to  reach  the  grapes  freely  and  to  evaporate  the  moisture  from 
their  surfaces  quickly. 

* '  Sheeping ' '  the  vineyard  or  allowing  sheep  to  eat  the  leaves  immedi- 
ately or  soon  after  gathering  the  crop  is  undoubtedly  a  bad  practice. 
It  removes  the  leaves  before  they  have  fulfilled  their  important  duty 
of  providing  the  reserve  food  to  be  stored  up  in  cane,  trunk  and  roots 
for  the  growth  of  the  following  spring. 

Thinning  the  Fruit. — Many  otherwise  suitable  grapes  do  not  ship 
well  on  account  of  the  excessive  compactness  of  the  bunch.  A  compact 
bunch  is  difficult  to  pack  without  injury  and  can  not  be  freed  from 
imperfect  berries  without  spoiling  good  berries. 

This  excessive  compactness  can  be  prevented  by  thinning  before  the 
berries  are  one  third  grown.  Thinning,  moreover,  increases  the  size  of 
the  berries,  hastens  ripening,  promotes  coloring,  and  lessens  some  forms 
of  sunburn.  The  practice  is  regularly  followed  with  success  by  many 
growers  of  Tokay,  Black  Morocco,  Luglienga  and  other  grapes,  where 
bunches  are  usually  too  compact.  While  apparently  costly,  the  expense 
is  often  more  than  counterbalanced  by  the  saving  in  trimming  of  the 
ripe  grapes.     The  increase  of  quality  thus  becomes  a  net  gain. 

The  bunches  are  thinned  at  any  time  after  the  berries  have  set  and 
before  they  have  reached  one  third  their  mature  size. 

No  bunches  are  removed,  but  only  a  certain  proportion  of  the  berries 
of  each  bunch.  The  number  of  berries  to  be  removed  will  depend  upon 
how  compact  the  unthinned  bunches  usually  become.  In  general,  it 
will  vary  from  one  third  to  one  half  of  the  total  number.  The  thinning 
is  effected  by  cutting  out  several  of  the  side  branchlets  of  the  bunch. 
The  branchlets  should  be  removed  principally  from  the  part  of  the 
bunch  which  has  most  tendency  to  compactness,  usually  the  upper  part. 
The  work  can  be  done  very  rapidly,  as  no  great  care  is  necessary  in 
preserving  the  shape  of  the  bunch.  However  irregular  or  one-sided 
the  bunch  looks  immediately  after  thinning,  it  will  round  out  and  be- 
come regular  before  ripening. 


—  38  — 

A  long,  narrow-bladed  knife  or  a  pair  of  grape- trimming  scissors  can 
be  used  conveniently  for  this  work. 

Ringing. — This  consists  in  the  removal  of  a  ring  of  bark  from  a 
growing  shoot  or  from  a  cane  of  the  previous  year.     The  ring  removed 


Fig.    14. — Black  Morocco  improved  by  thinning. 

varies  in  width  from  one  fourth  to  one  third  of  an  inch.  If  it  is  too 
narrow,  the  wound  heals  too  quickly  and  the  full  effect  of  the  operation 
is  not  obtained;  if  too  wide,  the  shoot  may  die  before  the  ripening  of 
the  fruit.  The  ring  is  removed  from  a  part  of  the  shoot  or  cane  just 
below  the  fruit.     This  prevents  the  passage  of  the  food  material  to  the 


—  39  — 

lower  parts  of  the  vine  and  causes  its  accumulation  in  the  parts  above 
the  incision  and  consequently  in  the  fruit. 

The  result  on  the  vines  is  weakening  as  in  all  kinds  of  summer  prun- 
ing. It  can  be  used  therefore  only  on  vigorous  vines,  and  usually  only 
on  those  parts  which  are  to  be  removed  at  the  following  winter  pruning. 

Shoots  may  be  ringed  as  soon  as  they  commence  to  become  woody  at 
the  base,  that  is,  a  little  before  blossoming  and  until  the  time  when  they 
commence  to  turn  yellow  or  mature.  The  canes  or  spurs  of  the  previous 
winter  pruning  may  be  "ringed"  from  three  weeks  before  blossoming 
to  a  month  before  the  ripening  of  the  fruit. 

Early  ringing  tends  to  cause  the  blossoms  to  set  better  and  to  combat 
"coulure."  It  causes  the  fruit  to  ripen  two  or  three  weeks  earlier  and 
often  to  increase  the  size  of  both  berries  and  bunches. 

Its  weakening  effects  are  greatest  in  hot  climates  and  it  is  not  used  in 
California.  In  Australia  it  is  used  regularly  with  the  Black  Corinth, 
the  vine  which  produces  the  small  seedless  grapes  from  which  the  cur- 
rants of  commerce  are  made.  This  vine  is  of  such  extraordinary  vigor 
that  ringing  may  be  practiced  every  year  without  injury.  It  is  even 
possible  to  ring  the  main  trunk  of  the  vine  with  good  results. 

The  ringing  may  be  done  with  an  ordinary  budding  knife,  but  can 
be  done  quickly  and  well  only  with  one  of  the  special  instruments  made 
for  the  purpose. 

Removal  of  Surface  Boots. — As  has  already  been  pointed  out,  the  final 
position  of  the  feeding  roots  depends  on  the  soil  conditions  and  can  not 
be  influenced  by  pruning.  The  position  of  the  main  roots  can,  how- 
ever, be  modified  to  some  extent  in  certain  cases. 

Young  vines  in  some  soils  tend  to  start  roots  at  or  very  close  to  the 
surface  of  the  ground.  This  is  especially  frequent  where  summer  irri- 
gation is  practiced.  If  these  roots  are  allowed  to  grow,  they  will  form 
main  roots  and  are  liable  to  injury  in  cultivation.  During  the  first 
and  second  year,  therefore,  it  is  advisable  to  cut  off  any  roots  which 
form  within  three  or  four  inches  of  the  surface.  This  can  be  done  at 
the  same  time  that  the  vines  are  hoed  and  suckered.  When  grafted 
vines  are  planted,  the  union  is  placed  above  ground  but  is  covered  by 
"hilling"  up  the  soil.  This  may  cause  roots  to  start  from  the  scion. 
These  roots  must  be  carefully  cut  off  before  they  become  large  or  the 
vine  will  fail  to  nourish  its  resistant  roots. 

Restriction  and  Treatment  of  Wounds. — The  possible  length  of  life  of 
a  vine  so  far  as  we  know  is  unlimited.  The  actual  profitable  life  varies 
from  a  few  years  to  fifty  or  more.  Vines  are  sometimes  killed  by  some 
disease  or  unusually  unfavorable  conditions  such  as  severe  frosts,  pro- 
longed drought,  etc.  Most  vines  fail  and  become  unprofitable  from  the 
effects  of  an  accumulation  of  small  injuries.     Among  the  chief  of  these 


—  40  — 

are  pruning  wounds.     Wounds  are  not  only  harmful  in  themselves  by- 
destroying  wood,  bark  and  other  conducting  tissues,  but  they  allow  the 


■■Mfea,                — .  jMllt.    U-                                 /"»•  '.^s-bv. 

\      dfefcgtfy^.         • 

:      ■       ;  ;"             \.  ■  -   ■-  ''•>  -:^yi 

.'• 

1'    **7*gl*i 

'■ '     ^'-  '^         '"■ .  :: 

I         \i 

lei"      .        'V'^    ."     .      '*■   i 
'  "?      /                           *  •*    £jfH 

Fig.   15. 


-Spore  bearing  bodies  of  an   "oyster-shell  fungus"   showing  fungous 
decay  of  the  trunk  due  to  large  pruning  wounds. 


entrance  of  boring  insects  and  wood  destroying  fungi  whose  effects  are 
even  more  destructive. 


—  41  — 

All  pruning  wounds,  therefore,  should  be  made  as  small  as  possible, 
especially  in  the  main  body  and  other  permanent  parts  of  the  vine. 
The  necessity  of  making  large  wounds  can  be  avoided  to  a  great  extent 
by  using  foresight. 

Useless  shoots  and  canes  should  be  removed  while  they  are  small  and 
young,  necessary  renewals  of  arms  or  branches  should  be  made  before 
the  part  to  be  suppressed  becomes  too  large.  Where  large  wounds  are 
unavoidable,  they  should  be  made  as  smooth  as  possible  and  protected 
by  an  antiseptic  swabbing  with  2  per  cent  copper  sulfate  solution  and 
covered  with  a  good  white  lead  paint.     The  vine  heals  its  wounds  from 


Fig.   16. 


-Proper  position  of  pruning  shears  with  relation  to  the  vine  when  mak- 
ing a  cut. 


the  inside  by  the  production  of  gummy  matters  or  thyloses  which  fill 
up  the  cells  and  tissue  and  so  prevent  loss  of  sap.  It  does  not  cover 
the  wounds  with  healing  tissue  from  the  outside  with  the  facility  of 
many  fruit  trees.  Wounds  much  over  an  inch  in  diameter  seldom  heal 
over  completely. 

By  careful  and  skillful  use  of  the  pruning  tools  the  harm  of  necessary 
wounds  can  be  reduced  to  a  minimum. 

All  cuts  should  be  made  clean  and  smooth.  This  requires  that  the 
shears  should  be  of  good  quality  and  kept  sharp.  The  cuts  should  be 
made  in  such  a  way  that  there  is  no  splitting  or  cracking  of  the  wood. 
This  is  accomplished  by  holding  the  shears  in  the  proper  way  at  the 
proper  angle  and  by  avoiding  any  undue  bending  of  the  portion  of  the 


—  42 


vine  to  be  removed.  Canes  for  spurs  should  be  cut  at  a  slight  angle, 
and  not  at  a  right  angle  to  the  grain.  In  cutting  off  a  cane  or  spur 
entirely  the  blade  of  the  shear  should  be  placed  against  the  vine,  and 
should  cut  upwards  as  shown  in  Fig.  16.  This  will  insure  a  clean,  close 
cut  without  splitting.  Any  cut  on  the  body  of  the  vine  should  be  made 
in  such  a  way  as  to  leave  as  small  a  wound  as  possible  and  at  the  same 
time  to  leave  no  projecting  stub.  Stubs  of  dead 
wood  prevent  healing  over  and  interfere  consider- 
ably with  future  pruning. 

In  spur  pruning  it  is  considered  best  to  cut 
through  the  bud  above  the  last  one  that  it  is  desired 
to  have  grow  as  at  C  in  Fig.  17.  This  leaves  the 
woody  diaphragm  intact  and  protects  the  spur  from 
injury.  If  the  spur  is  cut  at  Cx  a  long  piece  of 
^internode  is  left  exposing  the  pith.  As  this  pith 
dries  and  shrinks  it  allows  water  to  enter  and  forms 
an  excellent  place  for  molds  to  grow  which  may 
destroy  the  bud  below.  It  requires  some  skill  and 
practice  to  cut  exactly  in  the  right  place  and  if 
by  mistake  the  cut  is  made  just  below  the  dia- 
phragm the  breeding  place  for  molds  has  its  maxi- 
mum size.  For  this  reason  most  pruners  make  the 
cut  at  C2  about  half  an  inch  above  the  last  bud.  If 
the  shears  are  sharp  and  the  cut  made  at  an  angle 
of  about  45  degrees  behind  the  bud,  no  injury 
results. 

In  removing  a  piece  of  old  wood  at  the  base 
of  a  spur  or  fruit  cane  it  is  best  to  leave  a  little 
projecting  stub.  Too  close  cutting  in  this  case  is 
apt  to  injure  the  spur  or  cane.  The  projecting 
stub  can  be  removed  the  following  year,  when  the 
spur  has  grown  larger,  without  danger  of  injury. 
Supports. — With  most  systems  of  pruning,  after 
the  vine  has  reached  a  certain  stage  of  development 
and  its  framework  is  complete,  it  will  support 
itself  after  the  manner  of  a  small  tree.  Where 
the  trunk  is  elongated,  as  in  the  Cordon  systems,  the  trunk  requires  a 
permanent  support. 

Young  vines  in  all  systems  require  support  for  at  least  three  or  four 
years  and  usually  longer.  A  skillful  pruner  can  build  up  a  low  vine 
without  a  support,  but  the  results  are  imperfect  at  best  and  the  method 
requires  so  much  skill  and  care  that  there  is  no  economic  gain. 

In  long  or  cane  pruning,  there  must  always  be  some  support  furnished 
for  the  fruit  canes. 


Fig.  17. — Methods  of 
cutting  the  end  of  a 
spur. 


—  43  — 

The  supports  needed  then  are  of  two  kinds:  (1)  Temporary  supports 
to  keep  young  vines  in  place  until  their  trunks  become  large  and  strong 
enough  to  support  themselves,  and  (2)  Permanent  supports  for  long 
trunks  or  for  the  annual  fruit  canes. 

Staking. — As  temporary  supports,  some  form  of  stake  is  always  used. 
Nearly  all  vine  stakes  in  California  are  made  of  redwood,  which  is 
remarkably  adapted  to  the  purpose.  It  is  light,  easy  to  work,  and  very 
resistant  to  decay  unless  made  from  sap  wood.  Split  stakes  are  the 
best,  as  sawn  stakes  may  be  cut  diagonally  across  the  grain  and  many 
may  break  in  driving. 

Pine,  spruce,  poplar,  willow  or  any  available  wood  may  be  used  for 
temporary  stakes  if  redwood  is  unavailable.  Most  of  these  woods  will 
last  two  years  and  can  be  made  to  last  four  or  five  if  treated  with  copper 
sulfate.  Saplings  and  small  branches  can  sometimes  be  used  con- 
veniently. These  should  be  peeled  and  pointed  as  soon  as  cut  and  then 
stood  for  twenty-four  hours  in  a  tub  containing  a  few  inches  of  a  5  per 
cent  solution  of  copper  sulfate  (bluestone).  At  the  end  of  this  time, 
the  copper  sulfate  will  have  penetrated  the  whole  stake  and  can  usually 
be  seen  at  the  upper  end.  If  the  saplings  are  allowed  to  dry  even  for  a 
few  days,  it  will  require  a  very  much  longer  time  to  impregnate  them 
with  the  antiseptic. 

Other  materials  may  sometimes  be  conveniently  used  for  temporary 
stakes.  The  commonest  of  these  is  the  Spanish  reed  or  bamboo,  Arundo 
donax,  used  in  many  places  as  a  wind-break.  These  are  somewhat 
slender  for  the  purpose  and  require  much  readjusting,  but  will  serve 
when  better  is  not  available. 

The  length  of  the  stake  depends  principally  on  the  height  at  which 
it  is  desired  to  head  the  vine  and  on  the  character  of  the  soil.  It  should 
be  of  such  length,  that  after  being  driven  into  the  ground,  sufficient 
will  be  below  the  surface  to  keep  it  firm  and  prevent  its  being  loosened 
by  the  force  of  the  wind  acting  on  the  vine  which  is  tied  to  it,  and 
sufficient  above  the  surface  to  extend  for  two  inches  above  the  height 
at  which  it  is  intended  to  head  the  vines.  Its  thickness  should  be  in 
proportion  to  its  height. 

When  redwood  is  used  a  stake  thirty  inches  long  and  one  and  one 
fourth  inches  square  will  be  sufficient  in  firm  ground  for  small  growing 
vines  like  the  Zinfandel.  This  will  allow  fifteen  inches  to  be  driven 
into  the  ground  and  leave  fifteen  inches  above,  which  is  sufficient  for 
vines  to  be  headed  at  twelve  inches.  If  the  ground  is  loose  or  sandy,  a 
slightly  longer  stake  is  advisable.  For  strong-growing  varieties  such 
as  Carignan  or  Tokay,  especially  when  growing  in  rich  soil,  a  stake  two 
inches  square  and  thirty-six  to  forty-two  inches  long  is  necessary.  This 
will  permit  the  heading  of  the  vine  at  eighteen  to  twenty- four  inches. 


—  44  — 

When  a  stake  is  used  as  a  permanent  support  for  fruit  canes  it  is 
usually  made  six  feet  long  and  two  or  two  and  one  quarter  inches  in 
diameter.  A  somewhat  shorter  stake,  four  to  five  feet,  will  suffice  if 
the  canes  are  bowed.     A  similar  stake  is  needed  for  a  vertical  cordon. 

Trellising. — A  trellis  consists  of  one,  two  or  rarely  three  wires 
stretched  horizontally  along  the  rows.  The  wires  are  held  at  the  ends 
by  heavy  stakes  or  fence  posts  braced  firmly.  These  wires  are  sup- 
ported at  intervals  along  the  row  by  stakes  of  appropriate  height.  A 
tall  stake  at  each  vine  is  convenient  for  this  purpose  as  it  serves  also 
for  tying  up  the  yearly  replacing  shoots.  This  stake,  however,  is 
expensive  and  not  indispensable.  It  is  usually  sufficient  to  place  stakes 
at  intervals  of  two  or  even  three  vines.  Such  stakes  should  be  placed 
between  the  vines  and  need  be  long  enough  only  to  reach  to  the  top  wire. 

Some  growers  dispense  with  these  intermediate  stakes  altogether. 


Fig.  18. — Pruning  tools:    (a)   one-hand  shears;    (b)   two-hand  shears;    (c)   curved' 

saw. 

A  temporary  stake  is  used  with  each  vine  until  it  has  developed  a  self- 
supporting  trunk.  The  wire  is  then  allowed  to  rest  on  the  head  of 
each  vine.  If  the  vines  are  even  and  well  formed  this  is  a  convenient 
arrangement  as  it  facilitates  the  tightening  of  loose  wires  and  the  repair 
of  those  which  break. 

The  height  of  the  first  or  only  wire  is  usually  about  thirty  inches, 
that  of  the  second  forty-five  inches  and  that  of  the  third  fifty-seven 
inches  when  three  are  used.  In  many  cases  one  wire  is  sufficient  to 
support  the  fruit  canes.  In  windy  locations  the  second  wire  is  useful 
to  support  the  growing  shoots.  With  very  vigorous  vines  the  second 
wire  may  be  used  also  for  fruit  canes.  A  third  wire  may  be  used  in 
this  case  to  support  the  fruit  shoots,  but  is  seldom  or  never  really 
needed,  and  adds  much  to  the  cost  of  both  installation  and  maintenance. 
The  wire  most  used  is  No.  12  galvanized  fencing  wire.  No.  10  or  No.  11 
are  a  little  better  as  No.  12  will  frequently  break. 


M 


-  45  - 

For  the  horizontal  cordon  system  the  same  method  of  trellising  is 
used. 

For  attaching  the  vines,  canes  and  shoots  to  stakes  and  trellises  some 
form  of  rope  or  string  is  commonly  used.  The  balls  of  twine  used  on 
self-binders  are  convenient  and  preferred  by  some.  This  twine,  how- 
ever, is  not  quite  strong  enough  for  the  main  body  of  the  vine,  especially 
in  windy  locations,  unless  doubled,  though  it  is  excellent  for  tying  fruit 
canes  to  stake  or  trellis.  Old  ropes,  such  as  discarded  ship  cables,  can 
sometimes  be  obtained  cheaply,  and,  if  cut  into  suitable  lengths,  the 
single  strands  are  easily  separated  and  form  very  good  tying  material. 

It  is  false  economy  to  use  material  for  tying  of  insufficient  strength 
or  durability.  It  results  in  much  troublesome  extra  work  in  retying  or 
in  defective  vines. 

In  the  hands  of  very  careful  workmen,  nothing  is  better  than  wire 


Fig.   19. — Burning  the  brush  in  the  vineyard  after  pruning. 

for  tying  up  young  vines  at  the  winter  pruning.  It  holds  the  vine 
permanently  and  securely.  Used  carelessly,  however,  it  may  cut  the 
bark  and  unless  discretion  is  used  in  the  placing  of  the  tie  and  care  in 
its  removal  when  necessary,  the  vines  may  be  girdled  and  killed.  The 
wire  from  hay  bales  is  suitable  for  this  purpose  though  it  is  a  little 
unnecessarily  heavy.  No.  16  galvanized  fencing  wire  is  about  the  right 
weight. 

Other  materials  used  are  raffia  for  the  fruit  canes  and  osier  willows 
for  the  body  of  the  vine.  Raffia  is  unreliable  in  strength  and  inferior 
for  this  purpose  to  binding  twine.  Nothing  is  better  than  osier  willow 
to  attach  the  trunk  of  a  young  vine  to  the  stake  but  it  is  rarely  obtain- 
able and  requires  some  special  skill  to  use. 

Pruning  Tools. — The  best  tool  for  pruning  vines  is  a  pair  of  shears 
of  the  Swiss  form  (see  Fig.  18).  If  vines  are  properly  pruned  every 
year,  it  will  seldom  be  necessary  to  make  cuts  too  large  for  these  shears 
except  when  arms  have  to  be  replaced  or  last  year 's  fruit  canes  removed. 


—  46  — 

For  this  purpose  a  curved  saw  should  be  carried  by  the  pruner.  For 
vines  which  make  a  very  heavy  growth  or  which  have  been  unskillfully 
pruned,  a  pair  of  two-handed  pruning  shears  similar  to  those  used  for 
tree  pruning  may  be  used.  If  these  are  of  good  form,  kept  sharp,  and 
carefully  used  so  as  to  avoid  splitting  the  arms  or  cutting  too  deeply 
into  the  old  wood,  good  work  may  be  done  with  them. 

Disposal  of  Pruning s. — After  the  pruning  is  finished,  the  ' '  brush ' '  or 
cuttings  must  be  removed.  This  is  much  facilitated  if  the  pruners  are 
careful  in  placing  the  wood  they  remove.  The  usual  method  is  to 
place  the  wood  from  two  adjoining  rows  in  the  space  between  them, 
either  in  a  long  line  or  in  piles  between  four  vines. 


Fig.   20. — Vineyard  brush  burner. 

These  rows  or  piles  can  then  be  carried  by  hand  or  with  a  hay  fork 
and  concentrated  in  large  piles  in  the  avenues  or  on  the  borders  of  the 
vineyard  where  they  are  burned  as  soon  as  they  are  sufficiently  dry. 
The  heat  from  these  fires  is  so  great  that  it  sometimes  injures  neighbor- 
ing vines,  especially  if  the  burning  is  deferred  until  the  starting  of 
the  buds. 

A  better  method  is  to  use  a  brush  burner.  One  form  of  brush  burner 
is  shown  in  Fig.  20. 

This  consists  of  an  iron  truck  with  a  perforated  bottom.  A  fire  is 
started  in  the  truck  which  is  then  drawn  slowly  down  a  free  row  by  a 
quiet  horse  trained  to  the  work.  Two  men  collect  the  "brush"  in  the 
adjoining  rows  and  throw  it  into  the  moving  truck  where  it  burns 
without  danger  of  injuring  the  vines,  and  at  a  lower  temperature  than 


—  47  — 

in  the  large  piles.  The  ashes  are  distributed  equally  over  the  vineyard. 
The  method  is  difficult  to  adapt  to  trellised  vineyards  or  to  vines  with 
fruit  canes. 

Gathering  the  brush  with  a  hay  rake  is  sometimes  done,  but  is  not 
satisfactory  and  is  apt  to  injure  the  vines.  In  some  countries  the  vine 
primings  are  used  for  fuel,  for  manure,  and  even  for  cattle  feed,  after 
cutting  and  crushing.  The  labor  cost  in  California  seems  at  present  to 
prevent  economical  utilization  in  any  of  these  ways. 

Principle  of  Economy. — The  skillful  pruner  directs  as  much  as  pos- 
sible of  the  energy  and  growth  of  the  plant  into  the  permanent  frame- 
work of  the  vine  and  into  its  fruit.  The  unskillful  pruner  allows  the 
vine  to  grow  canes,  arms  or  branches  where  they  are  not  wanted  and 
which  must  be  cut  off  later.  This  is  not  only  a  complete  loss  to  the 
vine,  which  is  deprived  of  all  the  removed  material  which  ought  to  have 
gone  into  its  permanent  framework,  but  the  large  wounds  made  are  a 
source  of  weakness  and  shorten  the  life  of  the  vine.  The  skillful  pruner 
makes  use  of  the  vigor  of  the  vine  by  making  it  bear  all  the  fruit  it  is 
capable  of  bringing  to  perfection.  He  properly  distributes  the  fruit 
buds,  leaving  on  each  cane,  arm,  or  vine,  just  the  number  needed,  with- 
out running  the  risk  on  the  one  hand  of  weakening  the  vine  with  an 
over-supply  of  poor  fruit,  or,  on  the  other,  of  forcing  it  to  excessive 
vigor  and  sterility. 

To  avoid  waste  in  the  development  of  a  young  vine,  the  pruner  must 
have  a  clear  idea  of  the  form  he  wishes  to  give  it.  He  must  then,  by 
appropriate  and  timely  removal  of  buds  and  shoots,  force  the  growth 
into  those  parts  which  are  to  form  the  permanent  framework  of  his 
ideal  vine.  No  cane,  arm  or  division  should  be  allowed  to  grow  more 
than  one  season  which  is  not  destined  to  be  part  of  the  final  skeleton 
of  the  mature  plant.  In  this  way  the  vine  will  not  only  attain  the 
desired  form  but  will  quickly  reach  bearing  stature  and  be  free  from 
the  large  wounds  which  are  one  of  the  main  causes  of  premature  aging. 
Part  II  of  this  bulletin  will  contain  specific  directions  for  applying 
these  principles  to  the  principal  vines  and  regions  of  California. 


48 


TABLE  OF  CONTENTS. 


PART  I. 

A.     Introduction. 

Page. 

Literature:  Need  of  the  Bulletin 3 

Definition:  Objects;  Scope 3 

Some  Results  of  Defective  Pruning 4 

B.     Habit  and  Characteristics  of  the  Vine. 

Vitis  Vinifera  :  Structure  of  a  Cultivated  Vine   7 

Pruning  and  Descriptive  Terms 9 

Roots  ;   Trunk  ;    Head  ;   Branches  ;   Arms  ;    Spurs  ;    Fruit  Canes  ;    Buds  ; 

Shoots  ;  Water-sprouts  ;  Suckers  ;  Laterals  ;  Fruit  Wood  ;  Sterile  Wood. 

C.     The  Principles  of  Pruning. 

Physiological   Principles   22 

Winter    Pruning    . 23 

Season ;   Amount ;   Young  and  Old  Vines ;   Units  of  Pruning. 
Summer  Pruning   30 

Weakening  effect ;  Concentrating  effect ;  Uses  ;  Disbudding  ;  Thinning  of 

Shoots  ;  Topping  Young  Vines  ;   Suckering  ;   Water-sprouting  ;   Pinching  ; 

Topping ;    Defoliating ;    Thinning   the   Fruit ;    Ringing ;    Cutting    Surface 

Roots. 

Restriction  and  Treatment  of  Wounds 39 

Supports:  Staking;   Trellising   42 

Pruning  Tools:  Disposal  of  Prunings 45 

Principle  of  Economy  47 

ILLUSTRATIONS. 

Cover  Cut,  Wild  Vine  of  California   (Vitis  Calif ornica) . 

Fig.    1.  Trunks  of  V.  Californica. 

Fig.    2.  Root  crown  of  four-year-old  vine. 

Fig.    3.  Typical  cultivated  vine  with  short  arms. 

Fig.    4.  Typical  cultivated  vine  with  long  arms. 

Fig.    5.  Vine  "eye" — cross  section. 

Fig.    6.  Fruit  bud — cross  section. 

Fig.    7.  Fruit  bud — longitudinal   section. 

Fig.    8.  Sterile  bud — longitudinal  section. 

Fig.    9.  Shoot  showing  position  of  blossom  bunches. 

Fig.  10.  Shoot  showing  laterals  and  second  crop. 

Fig.  11.  Unit  of  short  pruning. 

Fig.  12.  Unit  of  long  pruning. 

Fig.  13.  Tokay  bunch  before  and  after  thinning. 

Fig.  14.  Black   Morocco   bunch   improved   by   thinning. 

Fig.  15.  Fungous  decay  due  to  large  pruning  wounds. 

Fig.  16.  Position  of  pruning  shears. 

Fig.  17.  Method  of  cutting  the  end  of  a  spur. 

Fig.  18.  Pruning  tools. 

Fig.  19.  Burning  the  "brush"  after  pruning. 

Fig.  20.  Brush  burner. 


